HI, This is all I have on Sync :

• https://support.mozilla.org/en-US/kb/how-do-i-set-sync-my-computer
• https://support.mozilla.org/en-US/products/firefox/sync
• https://support.mozilla.org/en-US/kb/how-do-i-choose-what-types-information-sync-firefox
• https://support.mozilla.org/en-US/kb/firefox-sync-troubleshooting-and-tips
• https://support.mozilla.org/en-US/kb/change-primary-email-address-firefox-accounts

Please still do backups as you never know what will go on with the above.

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Please let us know if this solved your issue or if need further assistance

Maybe first upload the bookmarks to Sync from one device and then disconnect that device. Then connect the other device and let it Sync to get the passwords from the other device. If you do not want the first device to get the bookmarks from other devices then you need to change the password of the Sync account to reset all data for before reconnecting only that single account. Data from all connected devices is always merged to all other connected devices, so you can't have other devices connected if you do not want to sync their data.

Thanks Pkshadow, but I read those topics before I posted the question. That didn't provide an answer.

I found out later that only the bookmarks in the Bookmarks Toolbar had been duplicated. I will do some more checking of what happened with differences in other bookmarks in the Bookmarks menu.

Thanks cor el,

I only want to sync my bookmarks, and I would like to have sync profiles,so that I don't sync all my PC bookmarks to my mobile phone for example. In X-marks I have different profiles for work, private, and mobile. I hope that Firefox developers (or extension developers) will work towards that functionality.

The purpose of Sync is to synchronize your selected data so that it is the same on all devices. There are no controls as Xmarks has as far as selecting which way bookmarks get synchronized. No "master" and "slave", either. With minor differences on "mobile" devices (Smart Phones and tablets), the selected data should be identical on each connected device.

Sync "Profiles" that is not a feature in Sync and probably will never be. The only "control" the user has is Sync across all devices; turn off what you don't want 'shared' on other devices. Or set up separate Sync / Firefox Accounts - the only way that might be accomplished, as far as keeping work, private, and mobile bookmarks separate.

I hope that you aren't attempting to use Sync and Xmarks on the same devices; that is a sure way to corrupt your data, which could be why you're seeing duplicates. My advice is to open Help > Troubleshooting Information and scroll waaay down to Places Database > Integrity and use the Verify Integrity button.

Then once you get results from that process, see if those duplicates on the Bookmarks Toolbar.

And it's a good idea to use Verify Integrity on all connected devices at the same time, with Sync disconnected.

Thanks edmeister,

I have turned off Xmarks, and also I have downloaded the En-US version of Firefox on my private laptop (before it was Dutch) so it is the same as on my work laptop. After that I have removed the duplicates, and now sync works as it should without duplicating anything.

I have also verified the integrity of both databases, and they were fine.

Thanks for the tips!

Best regards, Wouter