Try this

• https://support.mozilla.org/en-US/kb/firefox-sync-troubleshooting-and-tips

Remove the SYNC and reconnect it

Hello,

Sorry to hear about the computer breaking down. Are you able to access the hard-drive of the old computer? Was it a Windows machine? If so, you can locate the bookmarks on the hard-drive of the machine, by following the below mentioned instructions.

1. Locate the profile folder of Firefox on the old hard-drive by following these instructions Location of profile data
2. In the bookmarkbackups directory, copy the bookmarks-YYYY-MM-DD.json to your new machine on a different directory
3. Restore the bookmarks by following the instructions in this article Restore backups
4. This link from SUMO might also be helpful for you Copy and restore bookmarks

If the hard-drive is not accessible, then it will be difficult to access the bookmarks, if the synch was not enabled. Do you remember when the last synch happened?

Hope this helps.

Hello again,

thanks for your replies!

@iamjayakumars: I already tried to remove and reconnect twice, but it didn´t work. My guess is, that the latest bookmarks hadn´t been uploaded to the sync server before the old computer crashed.

@gnittala: Unfortunately I can´t access anything on my old computer. I sent it to Samsung for repair, but tried to run recovery before that (which delets all data, so my guess is, that nothing will be left when I get the computer back...). Actually sync was enabled. I really don´t understand, how so much is missing now -.-

Thanks again for your replies, but I think there´s no way to get tha data back after all.

It might be possible to removed the hard drive from the old computer and build it in and enclosure to connect it via USB to the currently used computer.