Trisha noted, “If users, who are affected by the DST update, call complaining that their all day appointments are now scheduled for 1AM to 1AM, you’ll need to install the following tool:

http://office.microsoft.com/en-us/outlook/HA102086071033.aspx

The following from William Lefkovics:

Daylight Savings Time (DST) Tool Update

I have been avoiding saying anything about the DST update process for Exchange, mostly because it is challenging to hit a moving target.

But I think today, we may be where we need to be to get this adjustment implemented on Exchange servers. Version 2.0 of the Exchange Calendar Update tool has been posted to the Microsoft download site. This one addresses resource mailboxes more effectively, with the Outlook tool, described in KB 931667, as a prerequisite. It has a couple of added command line options and manages public folder changes as well.

Look for KB 930879 How to address daylight savings time with the Exchange Calendar Update tool to be updated today.

Be wary of using internet searches and finding solutions prior to this version of the tool. I think the best resource for the process has come from the horse’s mouth, namely the Exchange Team blog, including videos on implementing the tool.