How to Register a File Extension in Regedit
- 1). Click the Windows "Start" button. Type "regedit" in the search text box and press "Enter." This command opens your Windows registry editor, which is sometimes referred as "regedit."
- 2). Click the arrow next to "HKEY_CLASSES_ROOT" in the left panel. This expands the list of file extensions registered with Windows. They are listed alphabetically. First, check to make sure the file extension is not already listed. If it is not listed, right-click "HKEY_CLASSES_ROOT," select "New" in the popup menu, then click "Key." Type your file extension name and press "Enter."
- 3). Right-click the file extension key you just created or found in your registry editor. Select "New," then click "Key." Type "OpenWithList" and press "Enter." This key tells Windows what programs to use when you double-click the file extension.
- 4). Right-click the new "OpenWithList" and select "New," then "Key" once more. Type the executable file name used to open the file extension. For instance, if you want to register the "docx" file extension for Word, type "wkswp.exe" and press "Enter."
- 5). Close the registry editor and reboot your computer. After you log in to Windows, double-click a file with the file extension you just registered to test the settings. The program registered with the extension automatically loads.
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