Apple Migration Assistant is one of the easiest ways to move from an old Mac to a new Mac or to restore information after a clean macOS installation. The interface looks reassuringly simple: select a few categories, click Continue, and wait for the transfer to finish.
But there is an important problem for anyone trying to perform a genuinely clean migration:
What does each Migration Assistant category actually copy?
That question becomes especially important when a Mac user account has been migrated repeatedly over many years. Copying everything is convenient, but it can also bring old application support files, preferences, background components and settings into an otherwise fresh macOS installation.
Apple explains the broad Migration Assistant categories, but it does not publish a complete file-by-file manifest showing exactly which directories, preference files and application databases belong to each option.
This guide explains what is known about the current Migration Assistant categories, what can reasonably be inferred from the way macOS stores data, and where Apple’s documentation stops providing precise answers.
Quick Answer: Migration Assistant Is Selective, but Not File-by-File Selective
Migration Assistant can selectively transfer major classes of information, but it is not a forensic migration tool.
Depending on the macOS version and migration source, the interface can include categories such as:
- Applications
- User Accounts
- Other Files & Folders
- Privacy & Security Settings
- System & Network
Some categories can be expanded to expose additional choices.
User Accounts, for example, can expose categories including:
- Documents,
- Pictures,
- Movies,
- Desktop,
- Downloads,
- and additional user information.
However, Migration Assistant generally does not offer checkboxes such as:
- copy this specific
~/Library/Application Supportfolder, - exclude this individual preference file,
- move Mail but not Messages,
- keep application database A but discard database B,
- copy application settings only if the corresponding application is selected.
This distinction matters enormously when the goal is to reduce years of accumulated software history.
Migration Assistant Categories: What They Really Mean
| Migration Assistant category | What Apple describes | Practical interpretation |
|---|---|---|
| Applications | Transfers applications | Application software that Migration Assistant considers transferable |
| User Accounts | Transfers selected user accounts and selected information belonging to them | Personal files plus substantial user-specific application and account state |
| Other Files & Folders | Transfers documents and files | Files that do not fit neatly into the selected user accounts, applications or settings categories |
| Privacy & Security Settings | Transfers privacy and security settings | Selected security-related configuration supported by Migration Assistant |
| System & Network | Transfers system and network settings | Supported Mac-wide configuration, with additional choices available in some versions |
The important point is that these are logical migration categories. They should not be interpreted as simple equivalents of individual Finder folders.
What Does “User Accounts” Copy in Migration Assistant?
The User Accounts category is much more significant than simply copying Documents and Desktop.
A macOS user account contains both visible personal files and a large amount of hidden application state.
A typical home directory looks approximately like this:
/Users/username/
Desktop/
Documents/
Downloads/
Movies/
Music/
Pictures/
Public/
Library/
The first several folders are obvious.
The hidden Library directory is not.
It can contain years of information associated with the user’s applications and macOS environment.
Common locations include:
~/Library/Application Support/
~/Library/Preferences/
~/Library/Containers/
~/Library/Group Containers/
~/Library/Mail/
~/Library/Messages/
~/Library/Safari/
~/Library/Calendars/
~/Library/Keychains/
~/Library/LaunchAgents/
~/Library/Saved Application State/
~/Library/Caches/
~/Library/MobileSync/
Not every folder has equal importance.
Some contain valuable user databases. Others contain temporary data or state that could simply be recreated by an application.
That is why migrating an entire historical user environment is fundamentally different from manually copying Documents, Pictures and Music.
Does Migration Assistant Copy ~/Library?
When a complete user environment is migrated, it is reasonable to expect substantial user-specific Library information to come with it.
Apple’s documentation for restoring from a Time Machine backup specifically describes Migration Assistant as being capable of restoring everything in a user account when the complete account is transferred.
What Apple does not provide is a public directory-by-directory list explaining:
- which parts of
~/Libraryare always transferred, - which parts are filtered,
- which caches are ignored,
- which version-specific data is transformed,
- which obsolete files are intentionally excluded.
That means anyone trying to achieve a very clean migration should treat a full User Accounts migration as potentially bringing a substantial amount of old user-level application state.
Why This Matters
Imagine an account that has existed since 2007.
During that time it might have used:
- several generations of Adobe applications,
- old browser extensions,
- multiple VPN clients,
- abandoned cloud services,
- printer utilities,
- old synchronization tools,
- obsolete menu bar utilities,
- software that is no longer compatible with current macOS.
The application itself may have disappeared years ago while some associated data remains inside the user Library.
A complete account migration can therefore preserve far more history than is visible from the Applications folder.
What Does “Documents and Files from Apps” Mean?
The wording of Migration Assistant can vary between macOS releases. Current versions may use a category such as Other Files & Folders, while other interfaces may describe additional documents and application files differently.
This is one of the least transparent parts of Migration Assistant.
Apple describes the category broadly as transferring documents and files, but does not publish a complete list of filesystem locations scanned by that category.
Therefore, it should not automatically be interpreted as:
/Library
or:
~/Library
or:
all application data
Migration Assistant categorizes information logically, and Apple does not provide a public mapping between every checkbox and every filesystem directory.
What Could Exist Outside a User Home Directory?
A Mac can contain information in many locations outside a normal user’s home folder, including:
/Library/Application Support/
/Library/Preferences/
/Library/LaunchAgents/
/Library/LaunchDaemons/
/Library/Fonts/
/Library/Printers/
/Library/Audio/
/Users/Shared/
Some third-party applications also create their own shared storage.
But the existence of data in these locations does not mean every file is necessarily transferred under a particular Migration Assistant category.
This is precisely the level of detail that Apple does not publicly document.
What Does “Computer Settings” or “System & Network” Transfer?
Modern macOS versions can separate settings into categories such as:
- Privacy & Security Settings
- System & Network
The System & Network category can also provide a disclosure control allowing additional choices.
This tells us something important: Migration Assistant does not simply copy every configuration file from the old Mac to the new one.
It understands at least some settings as migration objects that can be transferred selectively.
However, Apple does not publish a comprehensive table saying:
| Setting | Migrated? |
|---|---|
| Desktop configuration | Not comprehensively documented per version |
| Network configuration | Covered broadly by System & Network |
| Privacy permissions | Covered broadly by Privacy & Security Settings |
| Every System Settings preference | Not documented individually |
| Every preference in /Library/Preferences | Not documented individually |
| Every user preference in ~/Library/Preferences | Not documented individually |
This is important because macOS preferences are not stored in one universal “Settings” file.
Configuration can be associated with:
- the individual user,
- the entire Mac,
- a specific application,
- a network service,
- a security subsystem,
- an iCloud-synchronized preference.
There is therefore no simple rule that “Computer Settings” equals one particular directory.
What Does the Applications Option Copy?
The Applications category is one of the easier Migration Assistant options to understand.
Apple describes it as transferring applications to the new Mac.
It also warns that applications may not be transferred or may not work if:
- they are incompatible,
- a newer version is already installed,
- the software is otherwise unsuitable for the destination macOS version.
This is particularly relevant when migrating between macOS releases separated by several years.
A Mac application may appear to be one file in Finder:
Example.app
but many applications are not truly self-contained.
They may also depend on components located in:
~/Library/Application Support/
~/Library/Preferences/
~/Library/Containers/
/Library/Application Support/
/Library/LaunchAgents/
/Library/LaunchDaemons/
and other locations.
This leads to one of the most important Migration Assistant questions.
Are Application Settings Copied Only When the Application Is Selected?
Do not assume that they are.
The Applications category and User Accounts category are separate options in Migration Assistant.
An application itself may exist in:
/Applications/
while its user-specific settings and database exist in:
~/Library/
For example:
/Applications/Example.app
~/Library/Application Support/Example/
~/Library/Preferences/com.example.app.plist
Those are conceptually different pieces of information.
Apple does not document Migration Assistant as performing a universal dependency analysis where deselecting Example.app automatically removes every file associated with Example from the migrated user account.
Consequently, anyone trying to avoid old application settings should not rely on the Applications checkbox as a filter for the user’s Library.
Think of Applications and User Data Separately
A safer mental model is:
Applications = software
User Accounts = personal files plus user-specific state
The two interact, but they are not the same migration category.
Global Applications and User Applications
macOS supports software and data at different filesystem levels.
System-Wide Application Location
/Applications/
Applications stored here are normally available to all users.
User Application Location
A user can also have:
~/Applications/
although this is considerably less common.
System-Wide Application Data
/Library/Application Support/
User-Specific Application Data
~/Library/Application Support/
These distinctions help explain why Migration Assistant cannot be understood simply by looking at the visible Applications folder.
Modern applications may spread their state across several locations, and sandboxed applications can additionally use Containers and Group Containers.
What About Application Preferences?
User-specific preferences frequently live somewhere under the user’s Library.
For example:
~/Library/Preferences/
But modern macOS applications can use several storage mechanisms, including sandbox containers and synchronized settings.
This makes it unsafe to assume that deleting one .plist file completely resets an application or that every preference belonging to an application lives in the same folder.
What About Mail, Messages, Safari and Photos?
Apple’s own applications illustrate why selective migration can become complicated.
They frequently store information as databases, packages and internal data structures rather than collections of simple user-readable files.
Depending on configuration, information may also be synchronized through services such as iCloud.
Examples include:
- Mail databases and local mailboxes,
- Messages history,
- Safari history and settings,
- Passwords and Keychain information,
- Photos libraries,
- Contacts,
- Calendars.
For a clean migration, it is often better to decide how each important data class should be restored rather than assuming the complete historical user account must be migrated.
For a detailed strategy, see our guide to clean installing macOS Sequoia and selectively migrating data from an older Mac.
What Apple Does Not Tell Us About Migration Assistant
This is the part that can frustrate advanced Mac users.
Apple provides enough information to use Migration Assistant safely in a normal migration, but not enough information to treat it as a transparent filesystem migration utility.
The public documentation does not provide a complete list of:
- all transferred filesystem paths,
- all excluded filesystem paths,
- every migrated preference domain,
- every migrated privacy permission,
- every network preference,
- every cache Migration Assistant ignores,
- every compatibility rule used for applications,
- every relationship between an application and its user data.
That means questions such as:
“Will this exact folder inside Application Support migrate if I deselect the application?”
often cannot be answered definitively from Apple’s public documentation alone.
Why Doesn’t Migration Assistant Simply Copy Everything?
A migration between two Mac systems is not necessarily identical to cloning a disk.
The destination Mac may have:
- a newer macOS version,
- different hardware,
- different system files,
- applications that are already newer than those on the source Mac,
- different security requirements.
Apple explicitly states that Migration Assistant does not replace the operating system on the destination Mac.
Instead, it transfers user information, applications and supported settings into the destination environment.
This is an important distinction between migration and cloning.
Which Migration Assistant Options Should Be Selected for a Clean Mac?
There is no universal answer, because “clean migration” can mean different things.
Option 1: Maximum Convenience
Select:
- Applications,
- User Accounts,
- Other Files & Folders,
- Privacy & Security Settings,
- System & Network.
This is appropriate when the objective is to make the new Mac resemble the old Mac as closely as possible.
It is the easiest option but provides the least opportunity to remove accumulated software history.
Option 2: Fresh Applications, Migrated User Account
Deselect Applications and install applications manually.
Migrate the user account and selected settings.
This provides newer application binaries while retaining much of the existing user environment.
It can be a good compromise, but it may still carry old user-level application support files and preferences.
Option 3: Fresh Account and Manual Data Migration
Create a completely new account and manually move:
- Documents,
- Desktop files,
- projects,
- music,
- video,
- photo libraries,
- other known personal files.
Then allow cloud services to rebuild synchronized information and restore application-specific databases only when required.
This is the cleanest approach, but also requires the most work.
Option 4: Selective Migration Assistant Migration
This is often the best balance.
Expand every available Migration Assistant category and transfer only the information that clearly has value.
Then reinstall applications manually and keep the old Mac or old startup disk available for anything that was overlooked.
What Should You Do With a User Account That Has Been Migrated for 15–20 Years?
A long-lived account is not automatically damaged or inefficient.
But it almost certainly contains historical data that is no longer required.
Storage capacity has made this easy to ignore.
If storage becomes larger every time the Mac is replaced, there is little immediate pressure to decide whether a 14-year-old Application Support directory still matters.
The result can be an account containing several technological generations of software.
Instead of Asking “What Can I Delete?” Ask “What Do I Need?”
This is a much safer migration strategy.
Start with:
- documents that matter,
- current projects,
- photo and video libraries,
- local email archives,
- current application databases,
- credentials and recovery information,
- anything that cannot be downloaded or synchronized again.
Everything else can remain on the old disk until it proves necessary.
This approach avoids the impossible task of understanding every mysterious directory accumulated during two decades of macOS use.
How to Inspect an Old Mac Before Using Migration Assistant
Before deciding what to migrate, inspect the old user Library.
Open the User Library
In Finder:
- Open the Go menu.
- Hold the Option key.
- Select Library.
Useful directories to examine include:
Application Support
Containers
Group Containers
Preferences
Mail
Messages
MobileSync
Look for Large Directories
A folder being large does not mean it is unnecessary.
Large directories can contain:
- iPhone backups,
- mail attachments,
- creative application databases,
- browser profiles,
- cloud caches,
- developer data,
- messaging attachments.
Understanding the largest directories first usually produces better migration decisions than examining hundreds of tiny preference files.
Do Not Delete the Source Mac Before the New Mac Is Proven
Migration Assistant does not delete information from the original Mac.
That makes the old system extremely valuable during a selective migration.
If possible, keep the source:
- unchanged,
- bootable,
- and backed up.
Then use the new Mac normally for several weeks.
If an obscure application suddenly needs an old database, the source system is still available.
Migration Assistant Versus Time Machine
Migration Assistant can also transfer information from a Time Machine backup rather than directly from another Mac.
Apple describes Migration Assistant as being capable of restoring personal files, applications and everything in a selected user account from a Time Machine backup.
This makes Time Machine particularly useful during a clean migration because the old Mac does not need to remain physically connected throughout the process.
For individual forgotten files, however, restoring a specific file from Time Machine can be more appropriate than rerunning a broad migration.
Can Migration Assistant Be Run More Than Once?
Migration Assistant can be opened after initial Mac setup.
However, repeated migrations require care.
If an account with the same name already exists, Migration Assistant may offer options such as:
- replacing the existing account,
- keeping a copy of the replaced account’s data,
- renaming the incoming account so that both accounts remain available.
This is another reason to plan a selective migration before significant new data accumulates on the destination Mac.
Why Manually Copying the Entire ~/Library Is Usually a Bad Substitute
It can be tempting to create a fresh user account and later drag the old:
~/Library
over the new one.
That largely defeats the purpose of creating the fresh account.
The new Library may already contain:
- new databases,
- new application versions,
- new permissions,
- new synchronization state,
- new caches and indexes.
Replacing those directories wholesale with older versions can cause conflicts or erase information generated since the new system was installed.
Recover individual application data when necessary rather than replacing the complete Library.
Is There a Truly Detailed Migration Assistant File List?
Apple does not currently provide a public comprehensive filesystem manifest for standard Migration Assistant showing every path copied by every user-facing category.
That is why very specific questions about Migration Assistant often remain difficult to answer conclusively.
The most accurate approach is to distinguish between:
what Apple explicitly documents,
and:
what can only be inferred from macOS filesystem structure or observed behavior.
For the official description of the current categories and selection process, see Apple’s Migration Assistant documentation.
Apple also explains the broader Mac-to-Mac migration process in its guide to transferring information to a new Mac.
Frequently Asked Questions About Migration Assistant
Does Migration Assistant copy everything from the old Mac?
No. Migration Assistant transfers selected categories of documents, applications, user accounts and supported settings. It does not replace the destination Mac’s operating system.
Does Migration Assistant copy the entire user account?
It can migrate a user account and provides additional choices for certain types of user information. When restoring from Time Machine, Apple describes it as capable of restoring everything in the selected user account. Apple does not publicly document every individual filesystem path involved.
Does User Accounts include ~/Library?
A migrated user environment includes considerably more than visible Documents and Desktop files. A full user migration should therefore be expected to preserve substantial user-specific application state. Apple does not provide a public folder-by-folder manifest of the entire ~/Library transfer.
Does deselecting an application prevent its Application Support files from being migrated?
This should not be assumed. Applications and User Accounts are separate Migration Assistant categories, and application-specific user data can live inside the user’s Library.
Does Migration Assistant copy /Library?
Apple does not document Migration Assistant as simply copying the complete /Library directory. Some system-wide information may be handled through applications, settings and other migration categories.
Does Migration Assistant copy ~/Library/Application Support?
Application Support is part of the user’s application environment, but Apple does not publish a public rule stating exactly which Application Support directories are transferred or filtered under every migration scenario.
Does Migration Assistant transfer application settings?
Many application settings belong to the user’s environment rather than to the application bundle itself. As a result, migrating a user account can potentially preserve application state even when applications themselves are handled separately.
Does Migration Assistant copy network settings?
Current versions include a System & Network category for transferring supported system and network settings. The category can provide additional selectable items, depending on the macOS version.
Does Migration Assistant transfer privacy permissions?
Current Migration Assistant versions expose a Privacy & Security Settings category. Apple does not publish a complete per-permission manifest showing every security setting migrated in every macOS version.
Does Migration Assistant copy incompatible applications?
Not necessarily. Apple states that incompatible applications, or applications for which a newer version already exists on the destination Mac, may not transfer or may not be usable.
Should applications be migrated or installed fresh?
For maximum compatibility and cleanliness, reinstalling current versions is often preferable, especially when moving across several macOS generations. Migrating applications is more convenient when the source environment is recent and known to be healthy.
Can Migration Assistant migrate from a Time Machine backup?
Yes. A Mac, Time Machine backup and startup disk are supported migration sources.
Can Migration Assistant be used after Mac setup?
Yes. Migration Assistant can be launched later from macOS rather than only during the initial Setup Assistant process.
Does Migration Assistant delete anything from the old Mac?
No. The migration process transfers information without deleting the source data.
Is Migration Assistant the same as cloning a Mac?
No. Migration Assistant transfers supported information into the destination macOS installation. It does not replace the destination operating system with the source operating system.
What is the cleanest way to migrate a Mac that has been used for many years?
Create a fresh macOS installation and a fresh account, reinstall current applications, allow cloud services to synchronize current information, manually transfer ordinary personal files and restore only application-specific data that is actually needed.
Final Recommendation: Use Migration Assistant as a Migration Tool, Not as a Cleanup Tool
Migration Assistant is extremely good at what it was designed to do: move a working Mac environment to another Mac with minimal effort.
What it is not designed to provide is forensic control over every file accumulated during many years of macOS use.
If the objective is simply:
“Make the new Mac feel like the old Mac.”
then a broad Migration Assistant transfer is usually appropriate.
If the objective is:
“Preserve everything important but finally get rid of 15 or 20 years of accumulated software history.”
then a more selective approach is better.
The safest strategy is:
- Keep the old Mac or startup disk unchanged.
- Create an independent backup.
- Install macOS cleanly if a fresh start is desired.
- Expand every Migration Assistant category before selecting it.
- Do not assume the Applications checkbox controls all application-related data.
- Treat the user Library as an important part of the historical account state.
- Reinstall current applications when practical.
- Restore application-specific databases only when needed.
- Keep the original system available until the new Mac has been fully verified.
For a Mac account that has survived nearly two decades of operating-system upgrades, the goal should not necessarily be to determine the purpose of every old file.
A better goal is to identify the information that still has value and leave everything else safely on the old system until there is a reason to bring it back.
That is the difference between merely moving an old Mac environment and creating a genuinely clean new one.
For more Mac maintenance, migration and troubleshooting information, browse the latest macOS troubleshooting guides.