I lost all bookmarks when doing an update that asked me to create a profile when I'd never previously had a profile.

Hi,

You can't use Firefox without a profile, so you definitely had one before. Now you just need to switch back to the old one.

If you created a profile via the Firefox menu, please open the menu, click profiles and check which one contaibs your data.

Another place to check is the about:profiles page.

I only see 1 profile which does not have the old bookmarks. I may have inadvertently deleted the old profile when trying to create a new one.