If the profile folders are completely gone from /home/ubuntu18/.mozilla/firefox, it’s going to be tough to get them back. f you’ve been using a backup tool like Timeshift or something similar, you could try restoring your profiles from there. Or if you had Firefox Sync turned on, you could check if your profiles or bookmarks are synced to your account. Try logging in on another device and see if that works.

Yes, profile folders are completely gone from /home/ubuntu18/.mozilla/firefox. I'm not using any backup tool and sync is turned off. This never happened. Now before I try to use file recovery software (which I don't want to), I want to know if there is any solution. BTW, this is what I did: I used 'firefox -p' to delete one profile and result is this catastrophe. Also few days back I tried to open some profile folders which were in /.mozilla/firefox but not showing up in 'firefox -p'...That time firefox renamed all the profiles with a number suffix and kept the original folders