How to un-associate a file to NO application without choosing another application?

  • create a new textfile.txt,
  • change the extention .txt to .exe, choose accept changes
  • go to property in the file you wanna change the default app assocition to
  • Choose the textfile.exe
  • change back the extention of the textfile.exe to .txt and accept the changes.
  • Now the association is broken for the original file and it is set to NO assosiation.
  • Ref: