"Send to email client" where is this choice? I get "mail recipient" in file manager.

Is it perhaps on the menu of some application or other?

Mistake of mine, because I am so frustrated with the latest Thunderbird. It just makes everything harder to do. I have managed to get workarounds in place for most defects, but they shouldn't release a new version till it is user friendly.

I should have typed "mail recipient", but it still doesn't work. My work around is to open "New message", and drag the file in. I then have to add a subject, but it works. I would still like to know why my email client, which worked perfectly for the old Thunderbird, won't work for me on the new version. Is anyone able to help, please?

See I can right click and send to mail recipient.

Is your windows version 64bit? I have seen issues where the bitness? of Thunderbird and the application trying to send mail causes issues, but as far as sending to mail recipient I have had no issues wince I installed windows 10/11 on a new PC. I could never get it to work correctly on my PC have had been upgraded from XP.

My windows is 64 bit. However, the only thing that has changed is the version of Thunderbird. I have been through several versions over the years, but this problem only started when I was recently updated without my consent.

Tools > Settings > General > System Integration > "Check Now"