Problems with Tagging

I'm am using v 2.83 but have recently found a problem on tagging using the file file which included name/title/artist etc.
I used to click on file name tag and select format string. But when I click on the pull down menu it opens a blank window where there used to be list of various formats so you could choose the appropriate string.
I have tried uninstalling and re-installing - same problem. I have gone back to older versions same problem.

Any ideas?

The format strings which are shown in actions and in the convert menue habe been created by yourself in the past. They are the history of the strings you used in the past. Without your actitvity of defing theses strings there would be none at all.

You can delete them by clicking on the arrow at the right and select "Delete all from history".
Maybe you accidently delete them this way.

Never knew that function was there. Thanks for resolving the problem.