Windows applications associated with a file type are forgotten regularly

Hi,

I have been having this problem for a while now. I was hoping that the latest Parallels version would address the problem, but no luck. My issue is that the Mac OS is regularly "forgetting" the Windows application that is associated with a certain file type. Excel for .xlsx, to be specific. I have re-associate it frequently. Otherwise it will open in Mac OS Preview when I open the spreadsheet from the Mac finder.

Is there a way to fix this, so the file type stays associated with the Windows application?

Thanks