iCal to Exchange time errors

Generally, when iCal users receive and event invitation it gets added to the calendar properly, especially when the invitation was sent from a Mac. However, when sent from a PC that uses an Exchange server, the event time may be changed.

Apple Discussions poster awarrumbungle writes:

"When people invite me to an event from a PC, the event imports in at a different time (e.g. the meeting is at 8am but it displays at 6pm). This of course is extremely frustrating for many reasons! I have tried to turn on/off time-zone support but nothing seems to work."

This problem seems to only occur when the received invitation is from an exchange server, which indicates problems in the time conversion between the exchange server and iCal. As it turns out, this is in fact the case. Microsoft Exchange uses a time format that includes both an offset from GMT as well as a city location. For instance, an event created in the Los Angeles time zone (pacific time) would have the following format:

• (GMT 08.00) America/Los Angeles

• America/Los Angeles

This is fine, except that iCal does not read the Exchange time zone properly, and instead interprets the GMT offset as an event time offset, which in this case would advance the event by 08.00 hours from its original time. This problem needs to be addressed by either Apple or Microsoft, but in the mean time there is a fix available that users install as an applescript to run whenever an event is received. The script converts the time format on incoming events to that which iCal will recognize before the event is added to the calendar. This script is available at the following website along with detailed instruction on how to install it, and several Leopard users on the Apple Discussion boards have reported success with the installation.

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