We have an Exchange 2013 Server having issues after the daily backup procedure from Windows Server Backup. Clients (mainly ActiveSync devices) try to access the Exchange Server during the backup process and after, they get locked out due Throttling Policy of Exchange Server.

Was really difficult to discover this as an issue because the only error we can see was something like this:

Process w3wp.exe (AirSync) (PID=2212). The budget for user 'IF\ferrao_ApplDNPLQ39YFF
G8_iPhone' is locked out until 11/05/2014 13:52:48.  Max Burst: 240000, Recharge Rat
e: 360000, CutoffBalance: -600000

After sometime googling, the root of this problem can be resumed to Windows Server Backup slowing down the Exchange Server, and then Exchange Throttling Policy denying service to some clients.

There are some options, like creating a new ThrottlingPolicy with everything disable and them set it for all users or disable the backup process at all. But this cases doesn't appears to be good solutions for the problem, actually those options aren't a solution anyway. The first one is actually a hack that will be a impossible to maintain, since the new users will not get this new policy as default. And the second one is simply irresponsible.

I'm open to suggestion or solutions for this problem.

PS: I don't know if it's necessary but all servers are running Windows 2012 Server as guest machines under Citrix XenServer 6.2.


It seems like your server is in need for more capacity.
Add more CPU/RAM to it, as it seems to need it during Backup.

You could also balance the load to more servers (i.e. add another CAS/MBX Server, and back them up on different schedules)

  • Different CAS/MBX makes sense, but adding more CPU/RAM does not for me. We have only 600 users. The VM has 6 CPU's and 24GB of system RAM. It does not tops on those specs and it's only correlated to Windows Server Backup. Are you sure that CPU and RAM could be the issue, even if those resources are available? – Vinícius Ferrão May 12 '14 at 12:00
  • I'm having the same issue, and resources for the VM is not the problem. No matter how much RAM and CPU I give to the VM, this problem is still happening. – Maurício Mota Jun 23 '14 at 13:27
  • An old post I know, but have you checked disk activity on the VM host? If several VMs are running on the box it may be competing for disk read/write access with other servers – laurencemadill Jul 21 '15 at 13:42

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