Hi is possible it is a synchronization issue if using Sync. Please check your settings in your account.

I do not know if this effects that but there is an issue that only affects users who have turned off cleartype font rendering within their windows settings. so a workaround for the moment would either be to turn cleartype back on or disabling hardware acceleration in Firefox: Firefox's performance settings https://support.mozilla.org/en-US/kb/performance-settings

Please check the above and report back on that.

if is not the issue. please make sure have a backup then uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files , C:\Program Files(x86) & C:\ProgramData Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

• 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

Reinstall with Current Release Firefox 59.0.1 with a Full Version Installer

• https://www.mozilla.org/firefox/all/

Please update your Flash from ver 28 Flash Player Version: 29.0.0.113 Current Version https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, . . . .) Note: Other software is offered in the download. <Windows Only>

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

If you have sync, and there is a problem anywhere, Shut Down Sync Immediately On All Devices to prevent the problem from spreading. Once the problem is fixed, perform the same repair on all computers/profiles before using sync again.

Another possible cause is that places.sqlite is corrupted and that Firefox creates a new places.sqlite and rebuilds the bookmarks from a recent JSON backup. If that happens then you lose history, so you can check that.

In case you use "Clear history when Firefox closes" then try to disable this feature.

Use one of these to close Firefox if you are currently doing that by clicking the close X on the Firefox title bar.

• "3-bar" menu button -> Exit (Power button)
• Windows: File -> Exit
• Mac: Firefox -> Quit Firefox
• Linux: File -> Quit

Hey eyeryone and thank you for your efforts... I disabled the synchronisation and reset the bookmarks on my PC, laptop and phone. Now i want to see if the problem keeps happening.

Maybe an additional info i shoul've mentioned in the original post: this problem began a few days ago... if i remember correctly there was a little update for firefox? Maybe that causes the problem... I'll report back tomorrow :)

Edit: Just happend again... i have to work now but later i will check the other solutions you guys suggested...

I use an add-on that makes backups of my user profile, Just In Case. Unfortunately, it is not compatible with the current Firefox.

Every now and then, open the profile folder and create a copy of the current profile as is to another location on your hard drive. This way you will have a backup.

If you do this each day, you will not lose much data. This should be done with Firefox Closed.

Note: In case you need to restore from these backups, you may need to overwrite old or corrupted files.

Luckily Firefox does an automatic backup for my bookmarks, i can restore them and everything is fine, it's just annoying to restore them everytime and i thought maybe someone can help/ has a similar problem

Lich17 said

some of the bookmarks in my toolbar go missing every day

Do you know about when this happens?

FredMcD said

Lich17 said

some of the bookmarks in my toolbar go missing every day

Do you know about when this happens?

Okay, i just realized what the problem is... its my phone and the firefox app on it.

I just looked in the firefox app on my phone and saw, that there were no bookmarks at all (altough i use synchronisation)... then i did a manual sync and now the bookmarks on my pc are messed up again... thats where the problem seems to come from

Okay i reinstalled the app completly for my phone that seems to have fixed the resets... but now i have a new problem: my booksmarks from my bookmark toolbar dont get synced to my phone... i think it just synchronises the normal bookmarks but... i don't use them.. i only use the toolbar

Edit: should i close this question and post a new one with the new problem? Edit2: forget what i said, it still happens -.-

Okay my temporary solution is to not sync with my phone until the app gets fixed... thank you for helping me... if you have an idea what i can do concerning the app... let me know :)

If you have sync, and there is a problem anywhere, Shut Down Sync Immediately On All Devices to prevent the problem from spreading. Once the problem is fixed, perform the same repair on all computers/profiles before using sync again.

And to protect your data; I use an add-on that makes backups of my user profile, Just In Case. Unfortunately, it is not compatible with the current Firefox.

Every now and then, open the profile folder and create a copy of the current profile as is to another location on your hard drive. This way you will have a backup.

If you do this each day, you will not lose much data. This should be done with Firefox Closed.

Note: In case you need to restore from these backups, you may need to overwrite old or corrupted files.

Okay, its NOT my phone. I deactivated sync on it and its still happening... its getting annoying really fast

Is there anything else on the sync? What protection programs are you using?

FredMcD said

Is there anything else on the sync? What protection programs are you using?

I sync everything but the opened tabs. (and now i deactivated the bookmarks too).

And i use a german security program called "Avira"

I called for more help.