Video: How to rebase a Resource Calendar using the Outlook Time Zone Update tool and the /FORCEREBASESUPPRESSALL switch

In this video, we are demonstrating how to use the updated Outlook Time Zone Tool to update a resource mailbox. We are also demonstrating one of scenarios where a meeting item may become double booked if Direct Booking is used. Please view this to help you understand the process of updating your resource mailboxes.


For our previous video demos on DST subjects, please check this post.


If you have problems viewing the demo online or want to see higher resolution version, please right-click on the Download link under the video you are interested in and choose Save As...


NOTE: While the video specifically mentions Direct Booking resource, the procedure would be the same for Auto Accept Agent (AAA) resources. In that case, you should leave the resource registered with AAA and AAA should be running while you are performing the resource rebasing procedure.



- Steve Justice, Chris Burnham

Comments (13)
  1. JasonG says:

    So.. the only time you should have a conflict is if a users machine has been patched and they create the meeting after that update?

  2. Anonymous says:

    We have put together three demos that you can use to familiarize yourself with the process of running…

  3. colin says:

    We are considering using the /FORCEREBASESUPPRESSUPDATES with the Exchange Tool on all the mailboxes in our organization.    I have read that there is a further chance of duplicate or disappearing appointments but I can’t see an explanation of why.

    We would really like to avoid the confusion that all the updates will cause.

    My questions:

    1.  Is this a recommended approach?

    2.  Why would this approach cause greater risk of duplicate or disappearing appointments?

    3.  If used, I am assuming we would only run the Exchange Tool against mailboxes for users in areas to which DST applies.  We don’t run anything against the mailboxes in areas that do not use DST?

    Any help would be appreciated.


  4. mattm says:

    KB933146, under Option3 leaves some confusion.  With both step 1 and step 4 stating to make sure the AAA is running, it makes it seem like there’s a step to disable AAA missing.  Also, I’ve read it twice now, and I think that its saying to run with SuppressAll against ONLY the resource mailboxes, and then run again for all other mailboxes without SuppressAll.  Is this the correct interpretation?

  5. abdul says:

    From my understanding MattM i think you are correct… only against resource mailboxes… but it can be also run for single instance items. look at scenario one on the info regarding the hotfix.

    my question is …does the order matter..? should we do the Exchange tool against user calendars…and then the resource mailboxes?

  6. Brian says:

    I remember reading something about an XML file that needs to be updated before doing resources? Is this true still? If so how>

  7. Exchange says:

    abdul and MattM,

    You should do this against resource mailboxes 1st and then user mailboxes and here’s why:

    When you run this against the resource mailboxes, the tool will fix the appoitments but will not send out the updates (because of the switch). then, when you run the tool (without the switch) against user mailboxes, as organizers get their stuff updated, they will send out an update out, and a resource will be one of recipients. However seeing that this will be an update to the meeting that has already been fixed, the AAA will treat it just as an update and not a double-booking and will not reject it.

  8. Exchange says:


    No update of XML file needed for the new switch to work.

  9. Brian says:

    What new switch are you talking about? Also I just heard about a new switch in the MS DST chat rooms.  It is a /onlyprepatch switch. I am trying to find out more info no it? Here is an except below:

    Q: we have patched all desktops and servers with 931836. When we run the exchange calendar update tool 930879 all the items in the delta period have moved back one hour. Are we only supposed to run the exchange calendar update tool after 11th?

    A: The items that moved back an hour were probably created AFTER the patch. Unless you use the /ONLYPREPATCH switch, the tool has no way to distinguish between appointments made before the patch was installed (with incorrect rules) and AFTER the patch was installed (with correct rules) and it’ll rebase both.

  10. Exchange says:


    I was talking about the /FORCEREBASESUPPRESSALL switch. I have assumed that we are talking resource mailboxes here? If you use the /FORCEREBASESUPPRESSALL switch for resource mailboxes as the video from this post suggests, you do not need to modify the XML file in any way.

  11. abdul says:


    question regarding the last webcast on Thursday March 1st.  One of the techs answered a question regarding Exchange cached mode.  If we run the rebasing tools on cached mode the reminders will still be off.  However as the Admin and we are running it on a separate XP box than the users and each mailbox will be considered to be online, correct? so shouldnt the reminders be correct as well even though users are in cached mode.?  thnx again for your time and effort.

  12. Debra Dorn says:

    We ran our Exchange rebasing on all mailboxes and left the AAA and Public folders for last.  I’m not quite sure or clear on what switch can be used to run the tool on the resource mailboxes now after the fact.

  13. Anonymous says:

    I’m sure that’s the source of heartburn for IT Administrators all over the country right now. I just

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