icalexternalsync eats up all of my cpu whenever i put anything into ical. what is it and how do I stop it?

Greetings,

That process is used by iCal to communicate with other applications. Are you using another program for calendars / to dos like Outlook or Entourage (or did you in the past on an older computer)? If you are, turn off syncing in them and see what that does.

Try:

1. First make an iCal backup: Click on each calendar on the left hand side of iCal one at a time highlighting it's name and then going to File Export > Export and saving the resulting calendar file to a logical location for safekeeping.

2. Go to iCal > Quit iCal

3. Remove the following to the trash and restart your computer:

Home > Library > Caches > com.apple.ical

Home > Library > Calendars > Calendar Cache, Cache, Cache 1, 2, 3, etc. (Do not remove Sync Cache or Theme Cache if present)

--- NOTE: To get to "Home > Library" in Lion: Click anywhere on the desktop and then click on the "Go" menu at the top of the computer screen while holding down the "option" key on the keyboard. You will see "Library" in the menu.

4. Launch iCal and test.

If the issue persists:

1. Go to iCal > Quit iCal

2. Remove the following to the trash and restart your computer:

Home > Library > Caches > com.apple.ical

Home > Library > Calendars > Calendar Cache, Cache, Cache 1, 2, 3, etc. (Do not remove Sync Cache or Theme Cache if present)

Home > Library > Preferences > com.apple.ical (There may be more than one of these. Remove them all.)

--- NOTE: Removing these files may remove any shared (CalDAV) calendars you may have access to. You will have to re-add those calendars to iCal > Preferences > Accounts.

3. Launch iCal and test.

If the issue STILL persists:

1. Backup your computer Addressbook: http://docs.info.apple.com/article.html?path=AddressBook/4.0/en/ad961.html
2. Backup your computer iCal: http://support.apple.com/kb/HT2966
3. Backup your entire computer (its a good idea): http://support.apple.com/kb/HT1427
4. SafeBoot the computer: http://support.apple.com/kb/HT1455

   While in SafeBoot remove the following to the trash:

   • Macintosh HD > Library > Caches (All the contents of the folder not the folder itself)
   • Home > Library > Application Support > Sync Services (The entire folder)
5. Restart the computer and test.

Hope that helps.