Modify Windows Mobile 6.5 Registry File Associations

This guide explains how to change default file associations in Windows Mobile 6.5 using a registry editor. By navigating and updating specific keys within the system's registry, you can designate third-party applications to open specific file extensions instead of the operating system's default software.

Requirements

To edit the registry on Windows Mobile 6.5, you must install a mobile registry editor directly onto the device (such as Total Commander, Resco Registry, or PHM Registry Editor) or connect the device to a PC using a desktop remote registry tool.

Step 1: Locate the File Extension Key

  1. Open your registry editor on the Windows Mobile device.
  2. Navigate to the root key: HKEY_CLASSES_ROOT (often abbreviated as HKCR).
  3. Scroll down and locate the subkey corresponding to the file extension you want to change (for example, .txt, .mp3, or .pdf).
  4. Tap the key and check the value named (Default). This value references a Program ID (ProgID), such as txtfile or mp3file. Note this name.

Step 2: Navigate to the Program ID

  1. Return to the main list under HKEY_CLASSES_ROOT.
  2. Scroll down alphabetically to find the ProgID identified in Step 1 (for example, HKCR\txtfile).
  3. Expand the ProgID key and navigate deeper into the shell open structure: HKEY_CLASSES_ROOT\<ProgID>\Shell\Open\Command

Step 3: Update the Application Path

  1. Inside the Command folder, locate the (Default) string value.

  2. Edit this value to point to the executable file of the new application you want to use, wrapped in quotation marks, followed by "%1" to pass the file path.

    Example format: "\Program Files\NewApp\app.exe" "%1"

  3. Save the changes to the value.

Step 4: Alternative Method (Direct Extension Redirection)

If you prefer not to alter the existing ProgID or if one does not exist:

  1. Create a custom ProgID under HKEY_CLASSES_ROOT (e.g., HKCR\MyCustomApp).
  2. Add the subkeys: Shell -> Open -> Command.
  3. Set the (Default) value of Command to "\Program Files\Path\app.exe" "%1".
  4. Go back to your target extension key (e.g., HKCR\.ext) and set its (Default) value to match your custom ProgID name (MyCustomApp).

Step 5: Restart the Device

Registry changes regarding file associations do not always apply immediately. Perform a soft reset (reboot) on your Windows Mobile 6.5 device to clear the cache and enforce the new file handlers. Once restarted, tapping a modified file type in File Explorer will launch your selected application.