Reminders appearing for deleted events

I have recently started getting calendar reminders for two or three repeating events even though they have been deleted. I have tried repair but it did not solve the problem. The account is with

It began a day or so after a problem with a corrupt database which I had resolved by deleting folders.dat. I have no idea if the two problems are connected or not.

The reminder cannot be snoozed or dismissed. Double-clicking brings up its window but it is in an unusual format and cannot be edited in any way.

Any help would be greatly appreciated.

In the absence of any assistance from the company I decided to take a chance and deleted each of the events files in the database, after an appropriate backup.

On re-starting the application it took a long time for the database repair to complete, plus a couple of restarts, but my calendar was soon restored from the server and all now works very well. The mysterious read-only reminders have not returned.

As a bonus a problem with Windows taskbar pinning which began after an update a couple of years ago has gone away.