I fear compacting is frequently corrupted by antivirus programs.

Try right clicking the folder and selecting properties and then the repair button in the hopes that is is just an indexing issue.

Hi Matt - thanks for that - I tried indexing but still all files seem to be lost?

re :now only shows emails that have been starred

Please check to see if you have a filter in operation. 'Quick Filter' - it has an icon which can filter on 'starred' email, so only displaying anything starred. Is that option selected? - it would have a thin blue line on the icon - if yes, click on it to disable.

Or maybe the 'pin' icon is selected meaning it's applying a filter set previously on maybe another folder.