Solution to Thunderbird issues on Mac Big Sur
I wanted to share a workaround for Thunderbird issues with Big Sur upgrades on Mac. It seems that Thunderbird is having trouble accessing iCloud since the Big Sur upgrade, and as that is where the profiles, etc are stored, Thunderbird hangs or shows a blank page. This is an inelegant solution but actually does keep the whole system working (and my brain from imploding.)
Before opening Thunderbird, open Settings, then click on Apple ID up in the right-hand corner. When that screen opens, choose something from the left-hand column that accesses iCloud (either Name, Phone, Email or Password & Security) and click on it to open it. Once it does open, you can then click on Thunderbird and it will open normally.
Opaite Mbohovái (3)
Thunderbird profile storage on the cloud is not supported so it is little wonder there is an issue.
Is this new to Big Sur? Because I've had Thunderbird working well on my Mac for several years now and never had any issues until the Big Sur upgrade. Now it seems Thunderbird can not open until something else is accessed first on iCloud. Once it has, Thunderbird works normally for me.
IT has never been supported for any operating system, that is not to say some people have made it work for them. Others have created hundreds of copies of their files and data in the process and come here complaining about settings that will not save, odd files that turn up n the mail lists or even multiple copies of the mail folders with numbers.
I would guess this apple version has tighter restrictions on accessing icloud. You can probably modify the operating system to make the old process work, but the last apple computer I used had an 8" black and white screen some time in the 1980s. Personally I recommend just keep you profile on a local disk and accept that cloud storage and backup to synchronized locations of profiles is not going to be a good idea going forward.