Apple Mail application preferences corruption issue solution

I had an interesting problem with a client's Mail today. After migrating to a new i7 iMac Mail worked but crashed and had to forced to quit whenever you tried to edit the preferences.

After searching the web and Apple's support site with no luck I devised a plan to trash the ~/Library/Preferences/com.apple.mail.plist file and then manually rebuild the accounts. The mail in folders is unaffected by doing this but I made a backup just in case.

Before going to all this trouble we called AppleCare and we were bumped up to a Mail engineer that approved of my plan. But while talking we decided it was worth seeing if we could get the old iMac to re-write the prefs, then copy them to the new iMac.

I created a new email account on the old system. Closed Mail, which apparently did force Mail to re-write the preferences file, and copied the prefs over and it worked! The file's corruption was fixed.

Since this wasn't documented anywhere I decided to blog it myself.