# Chrome sync quietly joins accounts you meant to keep apart > Chrome sync files everything a profile does under one Google account, whichever account you used in the tab. Two accounts in one profile end up in one history. Source: https://mosaicbrowser.com/blog/chrome-sync-joins-accounts ## Chrome sync quietly joins accounts you meant to keep apart Chrome sync files everything a profile does under one Google account, whichever account you used in the tab. Two accounts in one profile end up in one history. ![Account A versus Account B, each name in its own tile: One Chrome profile, two Google accounts, one sync](https://mosaicbrowser.com/covers/chrome-sync-joins-accounts.webp) Chrome sync works per profile, not per account. A Chrome profile syncs to the one Google account you signed in to Chrome with, and everything that profile does goes to that account: history, saved passwords, bookmarks, extensions, open tabs, settings. Sign a second Google account in to the same profile through Gmail's account switcher and its browsing is filed under the first account too. That is the most common way two accounts get joined, and fingerprints have nothing to do with it. ## Chrome sync with multiple Google accounts: one sync account per profile Chrome has two kinds of sign-in, and they look alike. Signing in to Chrome, from the profile button at the top right, picks the account the profile syncs to. There is one per profile. Chromium's [design notes on multiple users](https://www.chromium.org/user-experience/multi-profiles/) say that when a user syncs, the profile's apps, autofill, bookmarks, extensions, passwords, preferences and themes are associated with the signed-in Google account and stored off the computer. Signing in to a Google website, such as adding a second account in Gmail's switcher, is only a web session. It puts a second set of cookies into the same profile's cookie jar. It does not change the sync account and cannot, because sync belongs to the profile. Mosaic is a desktop app Email yourself the link and open it on your computer. [How it works: Local first](https://mosaicbrowser.com/features/local-first) ## What the second account leaves in the first Say a profile syncs to your personal account, and you add a client's account in Gmail to answer one email. From that point, inside that profile: - Every page you open is saved in the profile's history, so with history sync on, the client's Drive files, its ad dashboard and the sites you visited for it all go into your personal account's synced history. - A password you save for one of the client's tools goes into your personal account's password manager, and then to every computer where you sign in to Chrome. - An extension you install for the client's work is installed for you, and appears on your other computers. - Both accounts share one cookie jar. Google's account switcher can list them together because both sessions sit in the same browser, so the pairing is visible to Google by design. None of this is a leak or a bug. It is sync doing what it says, across a boundary the person never meant to draw. ## The reverse direction It also runs the other way. Sign in to Chrome as the client in a profile that already holds your own data, turn sync on, and what was already there, your bookmarks and saved passwords included, goes up to the client's account. When Chrome offers to put a newly signed-in account in a profile of its own, that offer is the one to take. ## The free fix: one Chrome profile per account Chrome already has the right tool. Make a separate Chrome profile for each Google account, from the profile button and Add, and sign in to Chrome in each one with its own account, or not at all. Each profile then keeps its own sync, cookies, history, passwords and extensions. For a client whose access you hold through a Workspace address, the [Workspace approach to client separation](https://mosaicbrowser.com/blog/google-workspace-client-separation) keeps your agency from ever holding the client's password in the first place. What a Chrome profile does not separate is the computer. Every profile on one machine runs the same browser on the same hardware and leaves from the same network, so a site that reads the fingerprint or the IP sees one device behind both accounts. Sync is the link you make yourself, much like [Meta's Accounts Center](https://mosaicbrowser.com/blog/meta-accounts-center-joins-you); the device is the one you make without noticing, and [how to manage multiple accounts without getting linked](https://mosaicbrowser.com/guides/how-to-manage-multiple-accounts-without-getting-linked) goes through each signal a site compares. ## How Mosaic handles sync Every Mosaic profile runs in Tesseract Chrome, our own Chromium, and the engine launches each one with `--disable-sync`. A profile never syncs anywhere, so there is no sync account to collect two accounts' history. You can still sign in to Google inside a profile. Its cookies stay in that profile's jar, beside its own fingerprint and its own proxy exit, and the profile itself stays on your computer ([local-first](https://mosaicbrowser.com/features/local-first) has what is kept where). A Google account that sees a sign-in from a profile it has never met may ask you to confirm it; [why Google says "verify it's you"](https://mosaicbrowser.com/blog/google-verify-its-you) explains what it is comparing. Use it on accounts you are allowed to run. One Google account per person and per client, each in its own profile, is also the arrangement Chrome's own profile menu is built around. ## Questions ### Can one Chrome profile sync to two Google accounts? No. A Chrome profile syncs to the one Google account you signed in to Chrome with. Other accounts can be signed in on Google's websites inside that profile, but they never become the sync account. ### If I use a second Google account in the same Chrome profile, where does its history go? To the profile's sync account. Sync works per profile, not per tab, so pages you open while using the second account in Gmail or Drive are saved in the first account's synced history, and passwords you save go into the first account's password manager. ### Does a separate Chrome profile keep two Google accounts apart? It keeps their sync, cookies, history, passwords and extensions apart, which is the part most people need. It does not give them a different fingerprint or IP address, because every Chrome profile runs on the same browser, on the same computer and network. ### Does Mosaic sync profiles to a Google account? No. Tesseract Chrome launches every profile with Chrome sync switched off. You can still sign in to Google sites inside a profile, and the cookies stay in that profile's own jar on your computer. ## Related [How to manage multiple accounts without getting them linked](https://mosaicbrowser.com/guides/how-to-manage-multiple-accounts-without-getting-linked): Accounts get linked by shared cookies, IPs, fingerprints and habits. Give each its own profile, exit and history, then test it before you trust it. [Separating client work with Google Workspace accounts](https://mosaicbrowser.com/blog/google-workspace-client-separation): Give each person a Google Workspace account and let clients invite that address. Your agency never holds a client's Google password, and leaving ends access. [Accounts Center is a link Meta asks you to make yourself](https://mosaicbrowser.com/blog/meta-accounts-center-joins-you): Accounts Center joins your Instagram, Facebook and Messenger accounts: one login, shared contact details, payments and ad settings. Meta reads it as one person. [Why Google says 'verify it's you' on a new device](https://mosaicbrowser.com/blog/google-verify-its-you): Google asks you to verify it's you when a sign-in comes without the cookie its last sign-in left, or from an address in a place you have not been. [Local first: your profiles stay on your computer](https://mosaicbrowser.com/features/local-first): Mosaic has no cloud copy of your profiles. Profiles, cookies and proxies stay on your computer, encrypted on disk, with app lock, daily backups and a trash.  [Mosaic vs Multilogin: local engine or cloud platform](https://mosaicbrowser.com/compare/mosaic-vs-multilogin): Mosaic keeps every profile on your computer at one flat price. Multilogin syncs to its cloud, prices by profile count and adds cloud phones and teams.  ## Mosaic, on your own computer The browser this blog is about: its own Chromium, fingerprints from real machines and a proxy exit per profile. Free holds 3 profiles. Pro is $49 a month for any number. Mosaic is a desktop app Email yourself the link and open it on your computer.