Change back file type to “unknown application”

Mengubah atau mengembalikan file type  kembali menjadi “unknown application” (sudah ditest pada Win 7)

1. Click the “Start” button, type “cmd”, and press “Enter” while holding the “Ctrl” and “Shift” buttons. This runs the Command Prompt as an Administrator.

2. Click “Continue” in the confirmation window. If you are not currently logged in as an administrator, enter the administrator password.

3. Type “assoc .EXT=” in the Command Prompt window, replacing “EXT” with the actual file extension. Press “Enter” to remove the file association.

Or you can try to make changes in registry. Only do this if you are comfortable with registry editing.

1. Click the “Start” button, type “regedit” and press “Enter” while holding the “Ctrl” and “Shift” keys.

2. Click “Continue” in the confirmation window, or type the administrator password, if requested.

3.Navigate to “HKEY_CURRENT_USER\Software\Classes” in the Registry Editor. Right-click the extension under “Classes,” select “Delete” and click “Yes” in the confirmation window.

4. Navigate to “HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExt.” Right-click the extension under the “FileExt” folder in the left-hand pane, and select “Delete.” Click “Yes” in the confirmation window.

5. Test that the association has been removed by double-clicking it from Windows Explorer. If it opens an associated program, then continue the procedure. If it asks you to choose a program, then the association has been removed.

6. Hold the “Ctrl” key and press “F” to search the Registry. Enter “.EXT”, replacing “EXT” with the actual extension, and press “Enter.” Right-click any folder from the right-hand pane that is named after that extension, and delete it. This step may be unnecessary, but some programs place additional entries in randomly named folders.