Removing file type Associations on Windows

This has to be my second or third time looking this up within two to three years. That alone proves that it is easy to forget. However, it’s very useful when needed.

Ever accidentally not unchecked the “…and do this for all file types” check box? Now, you can undo that with the assoc command.

Examples

Using the Windows Command Prompt:

To see what application the .txt file extension is associated with:

assoc .txt

To set the .txt file extention to be associated to no application (disassociate it)

assoc .txt=

Reference