Per the article, yes, you have to. But if you read the article that says how Outlook stamps Calendar time, it makes it a little confusing as to why we need to run this tool. All calendar items are stamped with GMT. Then, based on the client Time zone settings, the Calendar item's time should be converted to the local time. So if the client and server are patched, it should be sufficient to convert the GMT stamps into local time. I am trying to research more into this. http://support.microsoft.com/kb/195900/en-us HTH. Regards, Raj Periyasamy MCSE(Messaging), CCNA ________________________________ From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Ara Avvali Sent: Thursday, February 08, 2007 1:38 PM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Re: How to address daylight saving time by using the Exchange Calendar Update Tool Is it necessary doing this if both server and clients are fully patched with wsus? From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Michael B. Smith Sent: Thursday, February 08, 2007 5:36 AM To: exchange-2003@xxxxxxxxxxxxxxx; exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] How to address daylight saving time by using the Exchange Calendar Update Tool It's live: How to address daylight saving time by using the Exchange Calendar Update Tool http://support.microsoft.com/default.aspx?scid=kb;en-us;930879 And the tool: Exchange Calendar Update Tool http://www.microsoft.com/downloads/details.aspx?FamilyId=A9336886-4B28-4 010-9416-36D38429438D&displaylang=en