I assume you are talking about sync? https://support.mozilla.org/en-US/kb/firefox-sync-troubleshooting-and-tips

https://support.mozilla.org/en-US/kb/sync-firefox-bookmarks-and-browsing-history-iOS Sync your passwords, history, tabs and other browsing information across your iOS, Android and desktop computers with Firefox Accounts

Yes; in the past, I've done factory resets on my machine and have been able to sign into Sync and had all my bookmarks restored. This time, Firefox restored my Extensions, etc., but not my bookmarks or saved logins, which is strange.

Is anything else missing?

It retained my home page settings and add-ons but lost all bookmarks and saved logins.

If you have a lot of bookmarks then it can take some time before they are all synced.

It is also possible that there is a problem with places.sqlite that prevents bookmarks from getting synced.

You can open about:sync-log via the location bar to see if there is a recent log available. You can upload a recent log if the log is too big to put in a reply.

• https://pastebin.com/

You can check for problems with the places.sqlite (bookmarks and history) and favicons.sqlite files in the Firefox profile folder.

• use "Verify Integrity" button on the "Help -> Troubleshooting Information" (about:support) page
  in case errors are reported close and restart Firefox and retry

See also:

• http://kb.mozillazine.org/Locked_or_damaged_places.sqlite
• https://support.mozilla.org/en-US/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file
• https://support.mozilla.org/en-US/kb/fix-bookmarks-and-history-will-not-be-functional

No bookmarks have loaded. Here are some lines from the end of the error log that seem like they may be relevant:

1549457908950 Sync.Synchronizer INFO Sync completed at 2019-02-06 07:58:28 after 54.67 secs. 1549457908951 Sync.Declined DEBUG Handling remote declined: ["history","passwords","tabs","bookmarks"] 1549457908951 Sync.Declined DEBUG Handling local declined: ["history","passwords","tabs","bookmarks"] 1549457908951 Sync.Declined DEBUG Declined changed? false 1549457908951 Sync.Service INFO No change to declined engines. Not reuploading meta/global.

Thanks!

Go to your 'good' computer and do this;

Back up and restore information in Firefox profiles.{web link} 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.