I took a Pop update today. After reboot Vivaldi (and only Vivaldi) wouldn’t start correctly; there were no icons or menu bar, so it had to be quit from outside.

I saw that this happened to someone else on a previous update. The same intervention worked. This will trash all of your bookmarks and other config. There’s probably a less scorched-earth way to dig out, but since I do use their sync service, this was an easy fix.

• Move/zip up/delete the ~/.config/vivaldi/Default directory
• Accept the onboard new user stuff.

Vivaldi sync is far from perfect. After re-establishing it, you’ll need to reconfigure all extensions you were running, and many of your settings will have been discarded, even if you said to sync them.