An Outlook user asked this question:
When I schedule a recurring meeting and the room is booked for one or more of the meetings, the room will decline the entire schedule of recurring meetings. How can I fix this?
This is not something an end-user can fix. The recurring event is declined because that is how the administrator has the Exchange server configured and you'll need to speak to the Exchange administrator.
If the administrator wants to change the settings and you are using Exchange Server 2010 or 2013, the Set-CalendarProcessing cmdlet is used to allow conflicts and to configure how many conflicts are allowed.
Set-CalendarProcessing -Identity "Room 2" -AutomateProcessing AutoAccept -AllowRecurringMeetings:$true -ConflictPercentageAllowed 25 -MaximumConflictInstances 3 -AllowConflicts:$true
In Exchange 2007 the Set-MailboxCalendarSettings cmdlet is used to allow conflicts and set the maximum number of conflicts and the percentage of conflicts allowed in a single recurring event.
Set-MailboxCalendarSettings -Identity "Conference Room" -AutomateProcessing AutoAccept -AllowConflicts:$true -AllowRecurringMeetings:$true -ConflictPercentageAllowed 25 -MaximumConflictInstances 3
More Information
For Exchange 2010 and 2013, see
Set-CalendarProcessing
For Exchange 2007, see
How to Set Resource Booking Policies
Set-MailboxCalendarSettings
Automatic Processing of Recurring Meeting Requests with Conflicting Instances
Alex says
So, if we leave the AllowConflicts=False, no matter what % or numbers we defined that will not make any difference.
I will try allowconflicts=true to check if it works.
AllowConflicts=false accept the request and send two emails back..one with accepted message and one with Declined because of conflicts instances.
Diane Poremsky says
Correct, that is how it's supposed to work.
Alex says
I think AllowConflicts:$true should be AllowConflicts:$false.
true overrides the % and number of instances. This something is experimented.
But my personal opinion is this is something wrong..Allowconflicts to false must not allow % or instances. false mean both sub permission level must not work..( but experint tells different story)
I will explain it in detail. Let me have some words from Diane.
Diane Poremsky says
Allowconflicts = True allows conflicts and the % and numbers tells Exchange how many is the maximum allowed. False ignores the % and number and won't allow any conflicts.
Phil Ready says
Hi Diane
using your example above
Set-CalendarProcessing -Identity "Room 2" -AutomateProcessing AutoAccept -AllowRecurringMeetings:$true -ConflictPercentageAllowed 25 -MaximumConflictInstances 3 -AllowConflicts:$true
I end up with double bookings.
If I use the same with -AllowConflicts $False, I get all bookings declined, not just the conflicts.
Is there something else I have to set?
I have same behaviour in Exchange 2010 and 2013
Thanks
Diane Poremsky says
That is how its supposed to work, it's all or nothing. It will accept the meeting if there are a few conflicts - 3 max, but no more than 25% if less than 12 in the series in this example. This does result in double booking on those days and you (or someone) needs to address the conflicts - move, cancel, find a new location, hope the other guy cancels his first, etc.
Phil Ready says
Thanks Diane. I was put crook by this article https://blogs.technet.com/b/exchange/archive/2011/02/07/3411956.aspx
A nice clear explanation, but obviously inaccurate. Do you have any comment on that article? might it be written from an early conception, or before a fix/change was needed?
David Ogborne says
Hello,
Are you sure allowconflicts should be set to True? This setting seems to overrule the conflict Percentage and MaximumConflictInstances settings and allows all conflicts to be booked. Setting it to False would be advisabled for the allowconflicts.
Diane Poremsky says
True should allow conflicts up to the % and max count levels. If its set to false, no conflicts are allowed.
From https://technet.microsoft.com/en-us/library/dd335046%28v=exchg.141%29.aspx "The AllowConflicts parameter specifies whether to allow conflicting meeting requests."
Phil Ready says
My testing has shown that AllowConflicts $True overrides % & Max setting. Do you think this is a design change, or a problem with my system or Exchange 2010/2013?
Diane Poremsky says
I'll have to test it. i don't think it is a problem with your system, it should either work or not work. if the max and % settings work with allowconflicts = false, then do it that way.
Martin says
Hello Diane,
What do you consider is the "Best practies" amount for ConflictPercentage and MaximumConflictInstances?
Best regards
Martin
Diane Poremsky says
It really depends on your business and how you use the resource. Do recurring events typically cover a lot of dates or just a handful? Generally speaking, 25% is a good conflict percentage. I would not go higher, under most circumstances. On maximum conflicts, 3 - 5, but again, it depends on your resource use.