When you delete emails the folders message "database" is also updated. This is actually more of an index used to list mails in the user interface. If this stuff is not updating, it is quite probable something is making access to the file difficult. My guess would be an anti virus scanning files while they are being updated and hence they are not being read. First instance would be to create an exception on the antivirus product for email scanning and on access scanning in the Thunderbird profile folder. The first to safeguard as your users do not sound very technical and having scanning on is a mess waiting to happen. The second to address your specific issue.

Other issues can be; Profile stored in the documents folders. Hard disk almost full so writes are getting quite slow Hard disk needs to be "defragmented" more often than not on widows systems over 6 months old with less than optimal free space and RAM installed. or even hard disk failing.

The list of things that can make a file access quite slow is really huge. But mostly is comes down to file access via antivirus or synchronization to the cloud of files that really should not be synchronized at all. So they get priority.

Hi Matt,

Thanks for the reply, I'll jump in over the coming days and have a look! I'll give exceptions a go first and see how this works out.