How to enable the "Always use the selected program to open this kind of file" checkbox
I found the answer at this now-closed (as off topic) Stack Overflow question: https://stackoverflow.com/q/2543254/253586
- Launch regedit.exe
- Navigate to the following subkey: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts
- Scroll down and find the file extension you are having problems with (for me it was .7z)
- Expand it to view its sub keys
- Find a sub key called "UserChoice" and delete it.