Based on my research, this issue looks to be tied to the recent windows update 1803 which looks to break some file associations with programs. This also possibly is related to some installed programs and/or the combinations of particular programs. This is a workaround regarding this issue until a more permanent fix is applied on windows' end via update as this is a known bug.


  1. Open up cmd as an administrator
  2. Type in the command ftype and the file type that the file in question corresponds to as well as the direct path of the desired program to open the file extension with : (ex. ftype txtfile="C:\Program Files (x86)\Microsoft Office\root\Office16\WINWORD.EXE" 


Now the desired program should now be opened with the corresponding program as the default going forward.