@DivineMaven yeah, I wanted to make sure I was seeing that properly. My first reading was thinking the only issue is you were getting logged out of everything. So seeing the idea of passwords missing from your password manager, it paints an extra picture.
Earlier 289wk linked to something which then also referenced something I said. It sounds like you’re in a situation where the DPAPI got corrupted. This happens in Chrome as well but isn’t always recognized by people because Chrome consistently syncs to your Google account. And for people who are actively using Sync here on Brave, it also isn’t necessarily noticeable.
If you’re not familiar with the terminology, Windows has something called the Data Protection API. It’s what they used to encrypt data on our devices. Apps like Brave or Chrome are able to use that for the encryption of passwords.
When updates happen to our OS or to the browser, sometimes something can “break” on that and the key gets lost. Without the key, it can’t unlock the encrypted information. And there’s not really a way to “fix” that. Unlike a physical lock, there’s no locksmith option and no creating a duplicate key. So it basically makes access to it again impossible.
Brave wrote a small thing about this at https://support.brave.app/hc/en-us/articles/29808985123085-Sensitive-data-storage but there’s not really much help in it.
What I may suggest, as annoying as it might be, would be to completely purge Brave from your computer and install again. What I mean by purge is that when you go to uninstall Brave a prompt will appear asking if you want to delete browsing history. You would need to check that so it will. This deletes all bookmarks, passwords, etc.
Obviously since you can’t access passwords right now, that’s not going to matter much. If you have any bookmarks still accessible you may want to export those first.
Once you purge Brave from your device and reinstall, it should have its new key. Then anything you save would stay saved. The next thing I’d suggest is you set up Sync if you haven’t been using it. Ideally you’d always have it working with a second device so it kind of serves as a backup. But if you have only one device, it might still be good enough just in case this type of situation occurs again.
Or you can just avoid using browser based password manager because of the potential risk and try to default to external passwords managers that save everything to an account. (or both)