Mail constantly opening and closing whilst trying to open for first time since El Captian install

[Didjt]

Help, mail is constantly opening and closing on first opening after el cap install. Makes all my other windows pulse and close. It has been like a video game trying to hit 'Quit' before the window disappeared again.
Have tried reinstall and Time Machine restore but reinstall did the same thing and restore didn't work!
My machine is useless and no mail.......

 

[arnekolja]

Did you find a way to fix it yet? I am having a similar issue. For me it is an old draft (that does not even exist in the mail account or something) constantly popping up, closing itself, and popping up again … in an endless loop.

 

[Didjt]

Any fixes yet, any one please, this is driving me mad, mad I tell you: so many other with same problem it appears.

 

[dfritchie]

I fixed it like this: Problem with MAIL after upgrading to El Capitan