Fix Firefox error opening site shortcut or HTML file

Sometimes, when you click on an internet shortcut or double click on a local HTML file, Windows gives error — Windows cannot find [URL or path to file]. This error is caused by Dynamic Data Exchange (DDE) feature of Windows. You can disable DDE for HTTP/HTTPS protocols and the HTML files to fix this error. Here is how :

1. Press the keyboard combination Windows logo key + R to bring up the Run dialog.
2. Type regedit in the Run dialog and press Enter.
3. In the Registry Editor, navigate to the following key,
   HKEY_CLASSES_ROOT\HTTP\shell\open
4. Select the ddeexec subkey and press the Delete key on your keyboard to delete it.
   
5. Similarly, delete the ddeexec subkeys under the following Registry branches too :
   • HKEY_CLASSES_ROOT\HTTPS\shell\open\ddeexec
   • HKEY_CLASSES_ROOT\FirefoxURL\shell\open\ddeexec
   • HKEY_CLASSES_ROOT\FirefoxHTML\shell\open\ddeexec
6. You will find that Firefox is now able to open the internet shortcuts and the local HTML files.