Surface Pro 4 with Hard disk Manager 15: Cannot restore to drive C

I have a daily incremental backup. Today, a windows update messes up and I lose my start menu and screen. When I go to restore yesterdays backup I can select the relevant backup file, but I cannot restore to Drive C. The error message is that a restore cannot be done to the same location. I have tried deleting the C partition first but I get exactly the same error message.

This seems madness. Replacing a damaged partition with a good backup is the most likely scenario.

If there isn't a simple answer to this then I think I've got to the end of the line with Paragon products.