Thunderbird slow/freezing after doing requested message compacting

If you got that compact message then it would be compacting all your folders. During that time it's advisable to not select any folders or emails and ideally go offline first to stop any emails incoming. Also do not exit Thunderbird. Did it complete compacting ? You would have seen a load of information in the bottom Status bar whilst it was doing compacting. Personally, I find it's just as easy to perform a manual compact on the folders that tend to get the most deletions or movements of emails. eg: Inbox, Spam and Trash eg: Right click on folder and select 'Compact' Do you have your Anti-Virus allowed to scan any file that gets opened ? If yes, then it could cause a delay or no response message etc. Advise is to access the Anti-Virus and set up an exception to not scan your '''Thunderbird''' folder that contains everything to do with your profile. If you download thunderbird from the official website: * https://www.thunderbird.net/en-US/thunderbird/all/ the '''Thunderbird''' folder to exempt from scanning is probably in this location: * C://Users/username/Apdata/Roaming/'''Thunderbird'''