The option to delete a file association is conspicuously absent from file associations user interface in Windows 7, so how can you delete file associations you no longer want? Read on as we explore how to remove a default file association.

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

The Question

SuperUser reader Christothes writes:

I somehow have set the default file type association for a file type in Windows 7. It doesn’t appear to be possible to delete it from the “Change the file type associated with a file extension” options screen. Is it possible to remove it?

While the tool for doing so definitely moved, certainly the option to remove a file association hasn’t vanished completely.

The Answer

SuperUser contributor Peter Mortensen offers the following solution:

Find the file extension in question under this key in the registry:


Deleting the sub-key with the same name as the extension you want to un-associate will delete the default program association. You’ll have to kill and restart explorer.exe for this to take effect.

You may also need to remove the same sub key from HKEY_CLASSES_ROOT as well.

It takes a little longer to root through the registry in search of the file association key than to use the old file association user interface, but it gets the job done.

Have something to add to the explanation? Sound off in the the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

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Jason Fitzpatrick is the Senior Smart Home Editor at How-To Geek. He has over a decade of experience in publishing and has authored thousands of articles at How-To Geek, Review Geek, LifeSavvy, and Lifehacker. Jason served as Lifehacker's Weekend Editor before he joined How-To Geek.
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