I use Thunderbird on several computers and my IMAP account contains several hundred thousand emails. In everyday use on my main computer this works very well and I have no problems with the speed of Thunderbird. If I open Thunderbird on a computer that I only use every 2-3 weeks, it becomes a real test of patience. Thunderbird updates, indexes and compresses about 50 folders in the background. As a result, Thunderbird is hardly usable for about 30 minutes. For example, if you want to write a new email (the most common case), the mail editor is extremely slow to use - characters entered only appear with a delay of 10-30 seconds, even though the computer is already very powerful with an SSD and a fast CPU. Is there a configuration option to run the mailbox update with such a low priority or to assign a high priority to the Mail Editor?