Does the same thing happen if you

• change folder pane from Unified Folders to All Folders?
• Start *Windows* in safe mode with networking enabled https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode, then still in Windows safe mode, start Thunderbird in Troubleshoot mode https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird ?

Thank you for getting back to me and sorry for the delay in responding. It happened that my computer crashed and I had to reinstall everything. Apparently things work now.

Sorry you had such great problems, and thank you very much for posting the reasons.

Why did you initially suspect "Storage Management - Intel Optane Memory." ?

Because just after updating the Thunderbird version it became very slow and then Intel Storage Management pointed problems

I have Thunderbird Supernova 115.5.2 64bit, and it is incredibly slow, both receiving emails, and moving to folders.

It never used to run as slowly, can anything be done to make the programme run more quickly?

I have Thunderbird Supernova 115.5.2 64bit, and it is incredibly slow, both receiving emails, and moving to folders. It never used to run as slowly, can anything be done to make the programme run more quickly?

@bluesky, the reporter's issue is resolved. You should create your own topic please.