• Right-click the Inbox

• Select Properties

• Click Repair Folder

This did not solve the issue, just fyi

Does it reproduce in Help > Troubleshoot Mode? WHat is your mouse device?

Hello there

Start Thunderbird in thunderbird right click on the folder , choose properties , and check the Retention policy settings. Go there , ensure it’s not set to keep indefinitely or for an extended period.

Greetings googlethunderbird.

Under Retention "Use my account settings" is checked; other choices are grayed out.

I haven't restarted in Troubleshoot mode so I don't know that answer. Since it doesn't do it every time I'm not sure I could reproduce it, or how many tries it would take to see if that happens. My mouse is a Logitech wireless.

Hello there

Please can you go to another pc and test that mouse? Can I ask?

Thank you.

I will try a different mouse, but it might be a few days before I know the outcome as it doesn't happen every time. Thanks for the suggestion.