Chrome profile sync: what travels and what stays put

A new Mac gets set up, Chrome is signed in with the same account as the old one, and within a minute the bookmarks are back and the extensions are reinstalling themselves. It looks like the whole browser has moved across. Then the first work tab opens and asks for a password, and so does the next one, and the illusion collapses.

That gap between what appears instantly and what has to be redone by hand is not a bug or a partial sync. It is the boundary of the feature, and it is drawn in a place that surprises people. Knowing where the line sits changes what a second machine, a rebuilt profile or a recovered account is actually going to cost in setup time.

Signing in and syncing are two separate switches

Signing into a Google website inside Chrome and signing into Chrome itself are different acts. Opening Gmail and entering credentials authenticates the site. It does not, on its own, start moving bookmarks and passwords into the account.

Sync is the second switch, turned on from the profile menu or from the settings page, and it is the one that decides whether anything leaves the machine. A profile can be signed into an account, showing the account's avatar, and still be storing everything locally. The reverse also holds: signing out of Chrome does not delete the local profile folder.

Chrome's help describes the effect of that second switch in one sentence.

When you sign out of Chrome, your info is kept safe in your Google Account and removed from the device. Source: support.google.com

Read that carefully, because it works in both directions. Signing out is not a way to clean up the account, and deleting a profile is not a way to clean up the device's account copy. The two stores are separate, and each operation touches only one of them.

What actually reaches the account

The categories are listed in Chrome's own documentation and they are worth reading as a list rather than as an idea, because the omissions are the interesting part. Bookmarks travel. Reading list travels. Passwords travel. Payment information and addresses travel. Extensions travel, meaning the list of what is installed, not the data those extensions have stored. Web apps travel. Settings and preferences travel.

History and open tabs are handled by a separate switch, turned on independently in the account settings, which is why a device can have every bookmark and none of the recent history.

The item that causes the most confusion is extensions. Sync restores which extensions should be installed, and the browser then downloads each one fresh from the store. The extension's own storage, its licence state, its logged in session and anything it saved locally are not part of that. An extension that arrives on a new machine arrives empty.

What never leaves the Mac

This is the part that decides how long the second machine takes to set up.

Cookies and site sessions do not sync. Every service that keeps a person signed in does so with a cookie in the profile folder, and those cookies stay on the device that created them. A new profile signed into the same account is signed out of every site on the internet. This single fact accounts for almost all of the disappointment with Chrome profile sync, because sessions are what people mean when they say the browser has moved across.

Local storage and indexed databases do not sync, so web apps that cache drafts, queued messages or offline documents start empty. Open windows and tab layouts do not sync as arrangements, even when the tabs themselves are visible in the tab list on another device. Downloaded files stay where they were downloaded. Per profile toggles such as which extension is allowed in incognito are properties of the local install.

Item	Reaches the Google Account	Notes
Bookmarks, reading list	Yes	Restores within seconds of signing in
Passwords, payment methods, addresses	Yes	Payment methods and addresses are not covered by a passphrase
Extension list	Yes	The extensions reinstall empty, without their stored data
Settings and preferences	Yes	Includes search engine, startup pages, theme
History and open tabs	Separate switch	Turned on independently, off by default in some setups
Cookies and signed in sessions	No	Every site asks for a password again on the new profile
Local storage, offline caches	No	Web app drafts and queues do not travel
Window and tab arrangement	No	Tab lists sync, layouts do not

Sync is a property of the profile, not of the browser

One profile signs into one Google Account, and that pairing is what sync operates on. Three profiles on one Mac can be signed into three accounts, syncing three separate sets of bookmarks and passwords, with no relationship between them.

This has a consequence people run into constantly. Bookmarks saved in a work profile do not appear in a personal profile on the same machine, because the two are as far apart as two different computers. Moving anything between profiles on one Mac means exporting and importing, or signing both into the same account, which defeats the reason the profiles were separated.

It also means the account is the unit of recovery, not the machine. Rebuilding a broken profile is a matter of creating a fresh one and signing it into the same account. Everything in the syncing categories returns. Everything in the second table does not, which is why the rebuild feels fast and the day afterwards feels slow.

Finding out what is actually syncing right now

Assumptions about sync are usually wrong in one specific direction: something the reader believed was on has been off for months. Three places give a definite answer, and checking them takes less time than debugging a missing bookmark.

The account settings page inside Chrome lists every category with its own control, reached from the settings menu under the section covering the Google account. This is where history and tabs is enabled or disabled separately from everything else, and where a passphrase would have been set. Reading down the list once per machine is usually enough to explain any discrepancy between two devices.

The account side has its own view. The Chrome data section of the Google Account dashboard shows what the account is currently holding, item by item, with counts. When a device shows fewer bookmarks than expected, comparing the count there against the local bookmark manager settles whether the problem is upload or download.

There is also a diagnostic page at chrome://sync-internals that reports the current sync state, the last successful update and any error the browser has recorded. It is dense and mostly aimed at developers, but the summary at the top answers one useful question directly: whether sync is running at all, or has been paused.

Pausing is the state that catches people out. When the account's session inside the browser expires, sync stops and the profile keeps working normally with a small marker on the avatar. Nothing breaks and nothing is lost, but nothing new reaches the account either. Weeks of bookmarks can accumulate in a profile that everyone involved believed was backed up. Signing back in resumes the upload, which is why the count on the dashboard can jump after a re-authentication.

The passphrase decision, and what it costs later

Chrome offers an optional passphrase that encrypts the synced data so that Google cannot read it. It is a reasonable choice, and it has consequences that are easier to accept before setting it than after.

The passphrase is required on every new device, and on devices already signed in. Saved passwords stop being visible on the password website. History stops syncing, except for addresses typed into the address bar. Payment methods and addresses are outside the passphrase entirely and are not encrypted by it.

Changing it later is not a small operation.

When you change your passphrase, the data encrypted by your passphrase is deleted from Google's servers and you're signed out from all your devices where you're signed in. Source: support.google.com

Exporting passwords before a passphrase change, and importing them afterwards, is the documented way to avoid losing them. Anyone considering the passphrase for a work profile should also check whether the organisation manages the browser, because a managed profile may have the choice made for it.

Setting up a second Mac with realistic expectations

Given the split above, the fastest sequence for a new machine is not the one most people follow. It puts the unsyncable work first, while there is still a working reference machine to copy from.

Start on the old Mac by listing which services are signed in and which of them use hardware keys, one time codes or device approval. Those are the ones that will take real time on the new machine, and knowing the list in advance turns an unpredictable afternoon into a known task. Anything protected by a code from an authenticator app also needs that app available before the browser work begins.

Then create the profile on the new Mac and sign it into the account. Bookmarks, passwords and the extension list arrive on their own. Wait for extensions to finish installing before signing into anything, because several of them intercept sign in flows and an extension that appears halfway through can leave a half finished session.

Next, work through the signed in services rather than waiting to discover them one at a time over the following week. Opening each one deliberately, signing in and confirming it stays signed in after a restart, converts a slow trickle of interruptions into a single block of work.

Finally, decide what happens to the old machine. If it is being handed on, signing out of the profile removes the local copies of synced data from it, and deleting the profile removes the folder. Doing both, in that order, is the version that leaves neither an orphaned entry in the profile list nor a set of live cookies on a machine somebody else will use.

When sync is being asked to do a job it cannot do

Sync is a settings replication service. It was designed so a person can move between their own devices and find the browser configured the way they left it. It was not designed to move a working state between machines, and it was certainly not designed to keep several accounts of the same service available at once.

The requests that sync cannot satisfy have a common shape. Staying signed into two accounts of the same chat service. Keeping one machine's window arrangement on another. Having a second Mac ready to work on without an afternoon of logging in. All three are about sessions and layout, which is precisely the half that stays on the device.

That half is where a different tool applies. When each web app has its own window with its own session, the arrangement itself becomes the thing that is defined once and reused, rather than something reassembled per machine from bookmarks. The structure behind that is described on the Workspaces page, the current list of what is covered is under Supported apps, and the questions that come up most often about how it coexists with an existing browser are answered in the FAQ.

What to change first

Open the account settings inside Chrome and read the list of what is being saved, because most people have never looked and at least one item is usually not what they expected. Then stop treating sync as a migration tool: it restores configuration reliably and sessions not at all. If the daily problem is signing into the same services over and over across accounts, that is a session boundary question, and SpaceDeck is built around it.