Thunderbird’s Archived Messages feature allows to move mails into the "Archives" folder by clicking the Archive button or pressing the a key.
For some of my mails, this doesn’t work. For these mails, the button is greyed out and the key doesn’t do anything.
What could be the reason for this? How to fix it?
Example: I enable the Archived Messages feature for an email account that has 1200 mails in the inbox. I select all mails: the button is greyed out. I start from the top and select mails until the button is greyed out, go back one mail, archive, and repeat. From these 1200 mails, 32 can’t be archived.
I restarted Thunderbird, compacted the folder, and opened the mails, but it still doesn’t work. I also repaired the folder, didn’t help.
(Workaround: Moving the mails manually into the Archives folder works fine.)