Since I installed groupy I noticed that when I click on an Excel file in file explorer, excel would open but not with the file I have double clicked on.  I  uninstalled groupy and that problem has been resolved.

This is a similar behavior to when you have the advanced option in Excel or Word checked to "Ignore other applications that use Dynamic Data Exchange (DDE)".    Windows explorer uses DDE to tell excel what file to open.   

When this problem occurs I did not have any windows grouped.