I have set Thunderbird as my default email client in Windows 11.
   MAILTO links work correctly when triggered from a browser or PowerShell (e.g., start-process "mailto:test@example.com" opens Thunderbird as expected).
   However, the "Mail recipient" option is completely missing from the "Send to" context menu.

   I have verified that MAILTO is associated with Thunderbird in the Windows default apps settings.
   The registry keys under HKEY_CLASSES_ROOT\mailto\shell\open\command are set to:
   "C:\Path\To\Thunderbird\thunderbird.exe" -osint -compose "%1"
   I have recreated the Mail recipient.MAPIMail shortcut in %APPDATA%\Microsoft\Windows\SendTo pointing to Thunderbird.
   I have reinstalled Thunderbird and checked MAPI compatibility, but the issue persists.
   Running rundll32.exe url.dll,MailToProtocolHandler test@example.com successfully opens Thunderbird.

   The issue seems isolated to the context menu functionality.
   The "Mail recipient" shortcut does not appear in the context menu at all, even after manually creating the Mail recipient.MAPIMail file in the SendTo folder.

Dear Support Team, I am experiencing an issue where the "Send to -> Mail recipient" option is missing from the context menu in Windows, despite having Mozilla Thunderbird set as my default email client. Steps to reproduce the issue: I have set Thunderbird as my default email client in Windows 11. MAILTO links work correctly when triggered from a browser or PowerShell (e.g., start-process "mailto:test@example.com" opens Thunderbird as expected). However, the "Mail recipient" option is completely missing from the "Send to" context menu. Additional troubleshooting: I have verified that MAILTO is associated with Thunderbird in the Windows default apps settings. The registry keys under HKEY_CLASSES_ROOT\mailto\shell\open\command are set to: "C:\Path\To\Thunderbird\thunderbird.exe" -osint -compose "%1" I have recreated the Mail recipient.MAPIMail shortcut in %APPDATA%\Microsoft\Windows\SendTo pointing to Thunderbird. I have reinstalled Thunderbird and checked MAPI compatibility, but the issue persists. Running rundll32.exe url.dll,MailToProtocolHandler test@example.com successfully opens Thunderbird. Observations: The issue seems isolated to the context menu functionality. The "Mail recipient" shortcut does not appear in the context menu at all, even after manually creating the Mail recipient.MAPIMail file in the SendTo folder. Could you please help me resolve this issue? Are there any additional settings or configurations I need to adjust to restore the "Send to -> Mail recipient" option for Thunderbird? Thank you for your assistance. Best regards, Ondrej