If so, then follow these steps to restore the functionality:
- Launch RegEdit (use at your own risk).
- Navigate to: \HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail\Mozilla Thunderbird in your registry.
- Check the key DDLPath. If it is empty, then proceed, if not empty, then STOP, you have a different problem.
- 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.