Windows Vista and Windows 7 allows you to change the program used to open a file. Sometime We set wrong association with file type and there is no option to revert back to default settings. So here is the only way to do that.

How To:

1. Run Registry Editor and navigate to: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\[Extension]
2. Expand the [extension] key and choose UserChoice key and delete all its sub keys
3. If it doesn’t work, delete the UserChoice key itself.

NOTE: To revert back to all default file association as we get after fresh clean installation of Windows Vista, We can delete all sub keys under FileExts.

Applies To:

• Windows Server 2008 R2
• Windows 7
• Windows Server 2008
• Windows Vista