I have a folder where I store e-mails about purchases I have made on line.
This has worked fine for several years and I clean it out once a week so has no more than 20 items in it.
As of yesterday (Oct 1st) the folder shows duplicates of some of the e-mails.
I cannot delete these duplicates.
Many of the remaining e-mails are empty.
It would appear that the database has corrupted?
How can I repair this folder?
If this is an IMAP folder, that means it is synced with your email provider, you should first verify that the contents are displayed correctly by using the web interface for your provider.
As long as the messages are not corrupt on the server, right-click on the folder in eM Client and choose Properties > Repair. That will delete the local message cache for that folder, and re-download the messages from the server. If your account is Gmail or G-Suite, you will need to right-click on the All Mail folder and choose Properties > Repair.