Since upgrading to El Capitan, I noticed the Mail application using a lot of CPU. About 80-90% sometimes.
Then going down to a few percent and then without any reason going up again.
Did a few times a "Rebuilt Mailboxes", but that did not help.
Any suggestions to repair this?
iMac, OS X El Capitan (10.11), 3.06 Ghz, 8 GB
After days of trying to get rid of the spinning pinwheel..this is the answer I have been looking for.
You maybe have saved an E-Mail as Template. Then Apple Mail comes into a loop (Software Bug since Apple Mail 8) with CPU as high as 180%.
Solution:
Go to:
~/Library/Containers/com.apple.mail/Data/Library/Application Support/Mail/Stationery/Apple/Contents/Resources/Custom/Contents/Resources
clean all E-Mails inside this folder. (you can move them to your desktop if you want)
restart Mail.
As long as Apple does not fix this Bug, you shouldn't use E-Mail Template functionality at all.
so far this has worked for me. Thanks
High Mail CPU with El Capitan
