TB freezes when deleting emails. Only anti-virus is Windows Defender.

Question

When I click on an email message and click one of the <delete> buttons, the little blue circle comes on, and I get a message "(not responding)". That is one click of <delete> for one email line. Usually happens after deleteing a few previous emails
TB 24.4.0. Windows8.1. Windows Defender. All up to date.
I checked. Do _not_ have McAfee, Norton, Avast, etc. on system or as Add-ons.
Tried restarting Windows 8.1. a few times. Problem remains.

Answer 1

I've seen this issue on every Win 8 installation as well. It seems to be caused by contention; Thunderbird and Windows Defender are doing a lot of disk IO on the same files.
The solution is simple: exclude the Thunderbird profile directory from being scanned by Defender.
Open Windows Defender (Start -> flick up or use down button with mouse -> Look for "Windows Defender" under the "Windows system" header).
Go to Settings, "Excluded files and locations" and use the Browse button.
Find c:\users\<your username>\AppData\Roaming\Thunderbird\Profiles
Select this directory, then press the "Add" button.
If the directory is shown in the bottom dialog, press "Save changes".
All done, Thunderbird should be ready to go, without performance issues.
@dev team: this might be something you want to automate!