My thunderbird updated now i can't open my old files, how can i fix this?

Hi ivan30, An update normally shouldn't prevent Thunderbird from accessing your existing mail, so I wouldn't delete or move any of the old files yet. This can happen if Thunderbird has started using a different profile after the update. Your old messages and settings are stored in your Thunderbird profile, separately from the Thunderbird program itself. Could you tell us which operating system you're using and which Thunderbird version you updated to? Also, when you say you can't open your old files, do you mean your old emails and folders are missing from Thunderbird, or that you have separate Thunderbird files on your computer that Thunderbird won't open? If your emails and folders have disappeared, please don't create a new account or delete any existing profiles yet. We can check Thunderbird's Profile Manager to see whether your previous profile is still available. Mozilla's current guidance specifically recommends checking the other profiles before making changes.