avast! doesn’t rename files unless you tell it to and that is after it detects an infected file and it offers move/rename as one of the options. The file rename would be originalfilename.exe.vir and not as you are showing
Are you saying this is what is happening e.g. avast detecting a virus ?
So I echo Tech question are you sure this is avast as I doubt it.
I think that you may have been tweaking avast, without knowing the possible impact and something is trying to rename that file (not avast) and avast is queering if it is OK to do so, see image.