Did your “Send To -> Mail Recipient” option in Windows quit working with Thunderbird?

If so, then follow these steps to restore the functionality:

1. Launch RegEdit (use at your own risk).
2. Navigate to: \HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail\Mozilla Thunderbird in your registry.
3. Check the key DDLPath.  If it is empty, then proceed, if not empty, then STOP, you have a different problem.
4. If DDLPath is empty, enter the path to the file “mozmapi32.dll” (most likely C:\Program Files\Mozilla Thunderbird\mozmapi32.dll)

This should correct the problem.