Why is mail running so slow

Question

Have the latest IMAC, running Mountain Lion, did migration from an almost identical mac, 2-years older, the mail program and filling out form boxes on web pages is a friggin nightmare, is aplle working on a solution? I see al ot of similar complaints.

Answer 1

I'm not sure if the Library/Preferences/com.apple.mail.plist the only problem is, but the com.apple.mail.plist is obsolete since Mountain Lion.
If you want to go sure, not to harm you OS, follow the steps:
STEP 1
Quit AppleMail. We will backup the com.apple.mail.plist. Open a Terminal. Same procedure as before, in Finder press SHIFT + CMD + U and you will be moved to /Applications/Uitlities. You see the Terminal app. Double-click it and a window will appear, in which you can type manually commands. After it starts, copy and paste following commands. After each line press ENTER. The 2 command lines always start with the command cp.
mkdir $HOME/bkkup-mail-plist
cp Library/Preferences/com.apple.mail.plist $HOME/bkkup-mail-plist/user-com.apple.mail.plist
cp /Library/Preferences/com.apple.mail.plist $HOME/bkkup-mail-plist/system-com.apple.mail.plist
STEP 2
In the steps before we create a backup-directory in your $HOME, named bkkup-mail-plist and copied the plist-files in this directory. One file which is system-wide used and the other used for your own preferneces.
In the next step we will remove this files. You will be requested with your password to delete one of this files, so type your password, which you use to login. Again, after each line press ENTER:
sudo rm /Library/Preferences/com.apple.mail.plist
rm Library/Preferences/com.apple.mail.plist
That's all. Because of your message, that the system-task for Mail is driven by a daemon (sandboxd), it could be you need to restart. Post if this solved your problem.