How to Fix the “SafariBookMarksSyncAgent Quit unexpectedly” Error

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Safari is the default browser for macOS and iOS devices, and it’s fast, efficient, and works well with Macs. It may not have as many add-ons and extensions as other browsers, but it has the necessary features for a fast and hassle-free web browsing experience on Mac.

Safari was designed especially for Macs and iOS devices. But this doesn’t mean that it is without flaws. One of the more recent problems Safari users encountered is the SafariBookMarksSyncAgent Quit unexpectedly. This error causes Safari to crash all of a sudden, causing users to lose their data or the progress of what they’re working on. Restarting the web browser does not help because users will just be greeted by another error message, which is:

Safari cannot be opened because of a problem.

This means that something was broken when Safari crashed the first time, making it unable to load properly again. The key here is to fix whatever caused the initial error before being able to launch Safari successfully.

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What Causes the “SafariBookMarksSyncAgent Quit unexpectedly” Error?

According to reports, some users encountered the error right after they upgraded to macOS Catalina while others got it after updating the Safari app. In both these instances, the cause of the “SafariBookMarksSyncAgent Quit unexpectedly” error is apparent. The change in either the browser software or the operating system made the app incompatible with the system. Software incompatibility is a common cause of most app errors.

Another possible reason is corrupted software. It is possible that a system file related to the Safari, particularly the SafariBookMarksSyncAgent, has been damaged or has become inaccessible, causing the error to keep on popping up on the screen. The SafariBookMarksSyncAgent is a core process of the Safari app and any trouble related to it will cause the browser to not function properly.

The SafariBookMarksSyncAgent is usually located here:


This Safari feature is responsible for syncing your bookmarks across all your devices and your iCloud account. An error in the syncing process could also be the reason behind the “SafariBookMarksSyncAgent Quit unexpectedly” error.

What to Do About the “SafariBookMarksSyncAgent Quit unexpectedly” Error?

Users who encountered this error are in a serious dilemma because they have no way to uninstall or reinstall Safari. Safari usually comes pre-installed with macOS so getting rid of it is a problem on its own. However, getting the “SafariBookMarksSyncAgent Quit unexpectedly” means not being able to use the Safari browser. Some users download other web browsers just to be able to browse the internet. But for those who’ve used Safari for most of their work and personal browsing, switching to a different browser is a huge hassle because you need to import all your bookmarks, saved settings, saved passwords, favorites, and others.

So if you prefer to fix this error to get Safari working again, we’re here to help you. We’ve listed down several solutions you can try to resolve this pesky error.

Fix #1: Update the Safari App.

If you’ve upgraded to macOS Catalina recently, you also need to update your apps, including the Safari browser. Just open the Mac App Store and look in the Updates tab for the latest Safari patch. Once you have updated your browser, restart your Mac and try to launch Safari again. If you’re getting the error after you updated Safari, try the next steps.

Fix #2: Clean Up Your Mac.

It is possible that the error is being caused by a misbehaving file somewhere in your system. Delete all unnecessary files using a Mac repair tool to try and resolve this error. You might also need to run your anti-malware software to make sure that there is no malware lurking somewhere on your Mac.

Fix #3: Delete Safari’s Preferences.

Another method you can try is to reset Safari’s preferences by deleting the plist file associated with the app. To do this:

  1. In the Finder menu, click Go > Go to folder.
  2. Copy and paste this address in the field: ~/Library/Preferences
  3. Look for and drag it to the Desktop.
  4. Relaunch Safari and see if the error has been fixed.
  5. If this method worked, drag the plist file to the Trash. If not, move it back to the Preferences folder.

You don’t have to worry about deleting the plist file because another plist will be generated the moment you open the app.

Fix #5: Boot into Safe Mode.

Several users tried booting into Safe Mode to fix this error, and it surprisingly works. To restart your Mac in Safe Mode, press and hold the Shift button while it boots. You can release the Shift key once you see an Apple logo and a progress bar on the screen. While in Safe Mode, try to launch Safari to see if the browser will load properly. If it does, then a third-party app or process is the one causing the problem. You can leave Safe Mode by restarting your Mac without holding the Shift key.

Fix #6: Sign Out of Your iCloud Account.

The SafariBookMarksSyncAgent is the process responsible for syncing your bookmarks with your iCloud account. When you get this error, try to log out of your iCloud account on your Mac using the steps below:

For Macs running Catalina:

  1. Click the Apple logo > System Preferences, then click your Apple ID.
  2. Click Overview found below your image and name.
  3. Click the Sign Out button.

For Macs running Mojave or earlier versions of macOS:

  1. Click the Apple logo and choose System Preferences.
  2. Click on the iCloud icon.
  3. Click the Sign Out button at the bottom.
  4. When the confirmation message pops up, click on Keep a Copy.

While you’re signed out, try opening the Safari browser and check if the “SafariBookMarksSyncAgent Quit unexpectedly” error has been resolved.


The “SafariBookMarksSyncAgent Quit unexpectedly” error can be troublesome because you won’t be able to use the Safari browser unless you fix the error. If you’re not used to using another browser or you still prefer Safari over Chrome or Firefox, you can easily resolve this error by following our troubleshooting guide above.

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