Thank you for the update @peterdew,
From your screenshot, it looks like there is a problem extracting the family templates.
This could be due to a bad download (i.e. the file is damaged/incomplete), or a problem with the permissions.
- I would suggest right clicking on the download and selecting to run as administrator (this should elevate the permissions of the process.
- If this doesn’t work, try changing the location of the extraction to a different folder (if this works, you could then copy/move the files to the default location).
- If extracting to a different location doesn’t work, try redownloading the file.
Regarding changing the program language, the following help topic has info on your options: Use Revit in Other Languages
The following article has information on: What changes when Revit uses ENG language versus ENU?
Regarding reinstalling Revit, if the issue is limited to the extraction of the template files from the download RVT20201_ENU_Metirc_FamTemplates_Templates, then I think we should focus on getting the files successfully extracted (i.e. the extract process indicates success and you can see the files in Windows outside of Revit).
Lance Coffey
Technical Support Specialist