The Exchange calendar will initially load correctly in iCal, but over time it starts to display an error with recurring events. The error is: "iCal can't save the event "EVENT TITLE" to the exchange server. The account can't be modified. To discard your changes and continue using the version of your calendar that is on the server, click Revert to Server. To save your changes on your computer until the problem is resolved. click Go Offline."

If you select "Revert to Server", it keeps going through all recurring events attached to the calendar. If you select "Go Offline", the errors stop but as soon as you go back online the errors return.

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This is related to time zone settings. You must complete both steps.

• Open iCal -> Preferences -> Advanced tab. Check 'Turn on Time Zone Support'.
• Open System Preferences -> Date & Time -> Time Zone tab. Check 'Set time zone automatically using current location'. You may see a message about turning Airport on; if you see it make sure wifi is turned on (even if you aren't connected to a network).