For old Thunderbird MBOX files, I’d first keep a backup of the original files and try opening/importing them directly in Thunderbird. If that becomes difficult, especially with multiple or large MBOX files, SysTools MBOX Converter can be another prac...
I agree that better Apple Mail and MSG support in Thunderbird would make migration much easier, especially on macOS. If Thunderbird’s built-in options don’t work, another workaround is to convert the mail files into a more compatible format first. I’...
If it’s just one Office 365 account, you can first add the account to Thunderbird using IMAP and let the messages sync. For a larger mailbox or when you want a more controlled migration, exporting the Office 365 emails to MBOX and then importing them...
If you only need to view a PST without Outlook, a dedicated PST viewer is probably the simplest approach. I’ve also used SysTools PST Viewer for this kind of task—it lets you open and preview mailbox data such as emails, attachments, contacts, calend...
If an old OneNote file won’t open, first keep a backup copy and try opening it with a compatible desktop version of OneNote. You can also check OneDrive or previous backups for another copy.If the file is actually a password-protected MS Word documen...
