Hello Graham,
My name is Nada I'm here to help you.
I'm sorry that you are experiencing this issue, and I will try my best to assist you.
It would be best to start by making sure that your Windows is up to date, this will help File Explorer to function properly. Kindly check if you have pending updates in Settings. You can use this link as your guide: https://support.microsoft.com/en-us/windows/upd...
I would also recommend for you to try using the System File Checker tool.
This will scan any system files that might be causing the problem. Here is the link where you can follow the steps: https://support.microsoft.com/en-us/windows/usi...
I hope this helps! Feel free to reach back in case you have more questions. I'll be more than happy to assist you.