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I had a file that Windows did not recognize. It was called abc.per. This is the correct extension for the file. The file does not open in any known Windows programs either (this is also not a problem). For some reason, I changed the file to always open with Notepad.

Now I want to get rid of the fact that it always needs to open with Notepad, but Windows just doesn't allow me to get rid of this behaviour. I tried to rename the file in which case it loses its extension, that is, per.

How do I remove the extension and restore the default behaviour of the file?

I am on a 64-bit Windows 7 system.

marked as duplicate by Karan, Tog, pnuts, tombull89, Journeyman Geek Jun 20 '13 at 11:25

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migrated from stackoverflow.com Jun 19 '13 at 11:09

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I was able to solve the issue. It was quite simple. I needed to go into the Windows Registry and remove the default associated with the extensions. The Super User post How do you remove a default program association for file types in Windows 7? is useful.

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