Have used Mozilla Thunderbird e-mail client on my desktop PC for many years under quite a few Windows operating systems, currently on Win 10 Pro, using multi accounts of my own and the wifes, always found the program to be very stable and reliable until a major update took place a few months ago.
Have encountered quite a few very annoying issues which I can't fix and have never been resolved with subsequent updates.
Such as:
Some account folders/sub-folders randomly fully expand when starting the program.
(yes, I have tried all the listed fixes for this issue)
Some account folders/sub-folders won't open, requires a program re-start to fix.
Some e-mails won't delete, requires a program re-start to fix.
Some e-mails colour tagging disappears, has to be re-applied then usually disappears again.
While reluctant to move away from Thunderbird where I have a lot of history, the random issues were becoming so annoying I decided I had to investigate migrating to another e-mail server application.
I use MS Office Pro Plus 2021 so have MS Outlook available, however it's not a straight forward conversion from Thunderbird to Outlook for all my archieved e-mail files, reluctant to go down that path.
Discovered "
Betterbird" which is a free non supported (by Mozilla) off-shute of Thunderbird.
Have been running this for a few weeks now, looks exactly like Thunderbird (without the recent issues), once the existing Thunderbird accounts have been set up again within Betterbird all data migrated automatically, very painless.
Betterbird just creates a new profile in the same area as the Thunderbird profile leaving the TB profile intact.
I have retained the Thunderbird installation just disabled mail collection for all accounts.
I use "
Backup4all" and the existing Thunderbird BU profile works perfectly for Betterbird without any changes.
So far so good, time will tell