iCal and MobileMe calendar have shifted times

For the past few months, MacFixIt has reported several issues in which users have had problems with strange time offsets when using 24-hour formats, as well as problems with the time zone formatting between iCal and Exchange calendars. Recently for some users have reported problems with iCal and the synchronized MobileMe calendars having shifted event times.

Apple Discussions poster Jack McDonald writes: "I've been having a HUGE issue with events posted to iCal and Mobile Me. No matter where I post/create and event/appointment, it shows up on the iCal/MM one hour different. [As such], my iCal on my Mac, my Mobile Me and my iPhone do not have the same start times."

iCal and MobileMe are integrated with the system's time settings but in addition both have their own time settings. If any of these settings are improperly set, users can experience time mismatches in their calendars.

Fixes

Set system Time Zone The first thing to do: check that the system's time zone is set correctly. Go to the "Date & Time" system preferences pane and in the "Time Zone" tab ensure both the correct time zone and closest city in that time zone are selected for the user's location.

Set the iCal and MobileMe Time Zone In both MobileMe and iCal there is support for time zone offsets to calendar data, which can be useful for users who travel between different time zones and need calendar data to always be accurate to the current time zone. To set this option in iCal, go to iCal's preferences and in the "Advanced" section check the option to "Turn on time zone support". Upon doing this a menu will appear at the top of the iCal window where users can select the current time zone. For users who do not use iCal in multiple time zones, it is recommended to disable this option. Likewise, this option is available in MobileMe. To access it, log into MobileMe and select the calendar. Then click the gear menu and select "preferences", and in the "Advanced" selection turn on the time zone support option. Then select the desired time zone.

NOTE: Users might try removing iCal's preferences file (named "com.apple.ical.plist" and located in /username/Library/Preferences/) as well, since a problematic preferences file can result in preferences not being saved or accessed properly.

Reset calendar sync date It may be possible that this time problem could be caused by a corruption in the synchronized data between iCal and the MobileMe "cloud". To reset the calendar sync data, open the "MobileMe" system preferences and click the "Advanced" button in the "Sync" tab. Then click the "Reset Sync Data" button and from the drop-down menu choose "Calendars" and then select the right arrow to replace the content on the MobileMe servers. Click "Replace" and the calendar data should be reset.

Completely reset synchronization resources If users cannot get the aforementioned fixes to work, a complete reset of synchronization data should fix the problem. This procedure will completely revert the system to the way it was before the initial synchronization with MobileMe, and then resync all data back to MobileMe again. The procedure for doing this is outlined in this MacFixIt article.

Resources