User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0

Steps to reproduce:

Try to attach a file from a windows folder to a new message creation window through the usage of Windows context menu "Send To"/"Mail Recipient".

Actual results:

No new message creation window opens in Thunderbird.

Expected results:

A new message creation window with the file attached should open in Thunderbird.

If TB is not opened, an instance of the program will open, but no new message creation window will pop up.

In the version previous to 60.5.2 the bug did not exist for me. Disabling addons did not help.

I can confirm that 'Send To > Mail recipient' no working on Windows 7 and on Windows 10 since today update to Thunderbird 60.5.2.

It is the same bug as in Bug 1531190 - https://bugzilla.mozilla.org/show_bug.cgi?id=1531190

They are duplicate bug reports for that issue...

Bug 1531190 Since update 60.5.2 - Send to > Mail recipient" on Windows no longer works. Windows 7
Bug 1531465 SEND TO MAIL RECEIPIENT STopped work in after update to 60.5.2

Another duplicate Bug 1531352 "Sent to mail recipient not working"

Duplicate bug list:
Bug 1531190 Since update 60.5.2 - Send to > Mail recipient" on Windows no longer works. Windows 7
Bug 1531465 SEND TO MAIL RECEIPIENT STopped work in after update to 60.5.2
Bug 1531352 Sent to mail recipient not working
Bug 1531678 MAPI doesn't work - "Send to mail recipient"

See bug 1530820 comment #30.