Edited by Joe AimonettiSome users have experienced an issue where Apple's Mail application will use 100% of the CPU and eventually fail, causing the system to slow down and overheat.
According to users in this Apple Support Discussions thread Mail will unexpectedly max out the CPU and eventually cause the entire system to overheat. Poster "Ranger Ric" reports:
"I recently noticed that my Macbook Pro was bogging down and overheating. Also, Mail would unexpectedly quit after about 30 minutes every day. Upon diagnosis I fond that the Mail app was running the CPU at 100+% all the time. I tried a fresh pref file and it did not help. The CPU should only run a few percentage points on Mail."The issue appears to be related to SyncServices and how it relates to managing Mail. With the help of a neighbor, "Ranger Ric" was able to devise this solution:
"Make sure Mail, Address Book and Safari are closed (write down these steps). In Terminal type:When attempting this solution, it is important that you create a stable backup of all your important data. If you are worried about possibly deleting contacts, export a vCard of your entire Address Book before attempting this workaround. Several users have reported that this fix seems to have solved the issue./System/Library/Frameworks/SyncServices.framework/Resources/resetsync.pl resetStart Mail again.
By the way, doing this will cause Sync to need to ask you whether you want to merge or overwrite data on either MobileMe or your computer. I assume everyone reading this post is familiar with the fact that if you choose merge you may duplicate every record in your calendar, address book, bookmarks, etc. If you know your local files are OK (and have made backups) I suggest you choose to overwrite MobileMe, but that is up to you.
This fix seems to work so far as Mail has been running cool now for a few hours. Post back with your experience."