Note: We have learned that customers using Exchange Server 2013 and Exchange Server 2007 co-existence can experience an issue causing Exchange Server 2013 CU6 databases to failover. Please refer to KB2997209 for the specific scenario impacted.

The Exchange team is announcing today the availability of our most recent quarterly servicing update to Exchange Server 2013. Exchange Server 2013 Cumulative Update 6 and updated UM Language Packs are now available on the Microsoft Download Center. CU6 represents the continuation of our Exchange 2013 servicing and builds upon Exchange 2013 CU5. The release includes fixes for customer reported issues, minor product enhancements and previously released security bulletins. A complete list of customer reported issues resolved in Exchange 2013 CU6 can be found in KB 2961810. Customers running any previous release of Exchange 2013 can move directly to CU6 today. Customers deploying Exchange 2013 for the first time may skip previous releases and start their deployment with CU6 as well.

We would like to call your attention to a couple of items in particular about the CU6 release:

  • As discussed at MEC 2014 and other forums, CU6 includes significant improvements in Public Folder scalability. More details about this in Public Folder Updates in Exchange 2013 CU6: Improving Scale and More.
  • CU6 includes a fix for the HCW issue discussed in KB 2988229. A reminder for those customers who installed the Interim Update which resolved this issue: it's NOT necessary to uninstall the Interim Update prior to installing CU6.

For the latest information and product announcements about Exchange 2013, please read What's New in Exchange 2013, Release Notes and Exchange 2013 documentation on TechNet.

CU6 includes Exchange-related updates to Active Directory schema and configuration. For information on extending schema and configuring Active Directory, please review Prepare Active Directory and domains in Exchange 2013 documentation.

Reminder: Customers in hybrid deployments where Exchange is deployed on-premises and in the cloud, or who are using Exchange Online Archiving (EOA) with their on-premises Exchange deployment are required to deploy the most current (e.g., CU6) or the prior (e.g., CU5) Cumulative Update release.

Note: Documentation may not be fully available at the time this post was published.

The Exchange Team

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I've had a similar experience to Aaron Marks, regarding obtaining the hotfix. Gone through multiple levels of MS support all telling me that the hotfix has been pulled. Even have a tech on the server right now, but doesn't seem to be getting too far (he

also is unable to obtain this illusive hotfix).

Don't see where i can escalate from here, if anyone can help me get my hands on the hotfix i would forever grateful. Case # 114090111757649

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@NahanHD, @Ackmania, @Peter, @OceanOB: We are still experiencing store crashes resulting in database fail over with the same signature, they are far less frequent. If you are on CU5 it is still worth updating, if you are pre-CU5 then I still wouldn't update.
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Anybody installed it?

Questions for developement team:

Was in CU6 fixed non-working sound notifications in OWA, broken since SP1?

Any imrovements with Rooms reservations? Now have a lot of issues with them...

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@PrabhatNigam - Please have your customers who are experiencing these issues reach out to support services for assistance. This will ensure that the issue is fully understood and a product response, if necessary, can be provided.
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Please TEST it in the lab 1st, and tell us here if All is well?

Heading to the lab myself :)

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We have just released KB2997355 to the Download Center. This package provides a PowerShell script which can be used to restore normal Exchange Administration Center functionality after an Exchange Server is upgraded to Cumulative Update 6.
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When can we expect to have the Set-MailboxSentItemsConfiguration cmdlet back? It is gone since the release of 2013 RTM and it's really annoying to be forced to use those legacy work-arounds which are time consuming and don't work half of the time!

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We loaded CU6 in our production environment last night. We had several issues with ECP, Address Book and PowerShell that were keeping the system from running smoothly. I would recommend running the CU6 before any cutover. It has turned our very smooth

for us. -John

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Do you have a list of feature changes in CU6 somewhere? Such as when you create a new shared mailbox, you can no longer designate a Send As permission during the creation. Actually, the creation was already cribbled in an earlier CU, when Full Access designation

was removed (maybe in CU4 or CU5).

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Yea, I'm having the same problem NathanHD. When are you guys gonna install CU6?
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@PrabhatNigam - Yes, we became aware of this issue earlier today. This happens when a 2007 user attempts to access a delegated mailbox that is on a 2013 server. This issue is being tracked by KB2997209, that is still being published.
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We got another hit for OWA issue in coexistence with 2007 post patching KB2997209. This issue is reported by Vince and Brett. We are tracking the issue here -


The latest resolution applied and posted by Vince is below:


That’s it, the only difference is that we have 15.0.995.30 and not the 15.0.995.31. What we tried was to stop World Wide Web Service then rename the 15.0.995.30 version to 15.0.995.30_Original. Copied the 15.0.995.29 into a new folder and renamed it as 15.0.995.30.

This way the 15.0.995.30 contained the files from the 15.0.995.29 version. Started the WWW Service and OWA seemed to work OK. This process was as per request from a Microsoft specialist who we still have an open phone call.


It will be great if you can give me some updates.

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And now I feel torn...

I'm just about to go live on a CU5 migration from 2007 in the next week or so, should I upgrade to CU6 and retest now or stick with CU5 and know what problems there are

My heart says CU6 but my head is saying CU5

And do the Dev team know if the UM language packs are going to get more transcription in the future?

I was gutted that US, CA and a number of other languages have this included but nothing for the UK.

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@OceanOB - That is exactly the issue we were having. All web services were slow and random disconnects. Outlook clients would not be able to connect to Address book or room finder.
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Sorry to be clear the issues we had were under CU5. They are all resolved with CU6. :)
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@Dmitriy - Command Line and unattended setup are still present in Cumulative Update 6. We no longer rely upon SETUP.com in Exchange Server 2013. Installation functionality is contained in SETUP.exe.
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@NahanHD, @Ackmania, @Peter, @OceanOB: We raised a case with MS on this as soon as we installed CU5, they have now confirmed the bug is fixed in CU6 - we have yet to install it, but will be doing so early next week. We are seeing failovers occur very frequently,

so will be able to confirm quickly.

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Thank you @JohnBair and @Peter4534532 for the information. This looks great for our installation. I only wonder why the MS guy taking care of our call didn't tell us that the cause of the frequent failovers was already known and that it would be solved

in CU6.

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Ackmania: we are installing in a few days.
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I would hold off on CU6 if you're a 2013 hybrid customer, too.



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Thanks, Brent, I have confirmed that the script does fix the EAC issue. I have updated my blog article with installation notes here:


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@Jeff Guillet - You are correct, a solution is in the works for this (even over a holiday weekend).
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So I wasn't the only one with random daily database switch-overs! I have not really looked into it much as the process is seamless, however, backups are not too happy with this. If this doesn't help that, time to open a call.
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regarding 2991934 (http://support.microsoft.com/kb/2991934/ ) Duplicate mailbox folders after migration to Exchange Server 2013 - we have CU4/SP1 in place and migrating mailboxes from E2007 - under

what cicumstances this issue will appear? We indentified until now two affected users (more than 1000 migrated)

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FYI - I received a combined hotfix for the Exchange 2013 CU6 issues (Exchange 2007/2013 DB failover/ActiveSync problem) yesterday. You'll need to work with Microsoft Support to receive fix.
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Just finished 2 servers installation in lab, S1 installed perfect but on S2 some services were not started automatically so I started manully. I think it is because of my lab.

Then created IP Less DAG and 2nd copy of the DB.

Tested move DB to S2 then mailflow then move the cluster group to S2. All worked great.

Earlier even in IP Less DAG, we were able to access the cluster from failover cluster manager by using dot but it seems this feature has changed in CU6. Can anyone confirm?

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@Bendoubitibly - Exchange 2007 update has released and tested. It is solving the issue. So make the use of it.
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After the installation new Exchange Edge 2013 CU6 does not start service MSExchangeHMHost. error 7003 - Service "Health Manager Microsoft Exchange" is dependent on the following services: "MSExchangeADTopology". Perhaps, this service is not installed.

Updated Exchange edge 2013 cu5 to cu6 - problems are not observed.

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Good, but why on the first server edge (updated) service is started and running?

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Whats going on with the language packs, the link is broken. Have they been published yet? Can anyone else download them?
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@Peter4534532 - We were not aware there is an issue downloading UM Language Packs. We will investigate and correct as necessary. Thank you for reporting this.

@Martijn Westera - We do not expect Hybrid customers to fall behind. They need to ensure that they are remaining currency. Hybrid customers should be using CU5 or CU6 at this point.

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Deployed CU6 to a small production environment (2 Server DAG with 200 Users).

Went mostly smooth, the only thing I noticed is that a complete index re-crawl happened. (after upgrading node 1)

Took almost half a day for 150GB in 3 DBs. Server has 4 cores and 16gb, storage is iscsi raid10.

Quite long for that tiny DB, next week I will update a larger environment with 2TB Data. I hope it doesnt have to re-crawl.

After upgrading node 2 its content index state was stuck on unknown (events 1009 and 1010 were logged), I created the group "content submitters"

http://support.microsoft.com/kb/2807668 and finally updated the catalog from node 1.

all good since then.

Before upgrading a node I put it in maintenance using $exscriptsstartdagservermaintenance.ps1.

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What a ridiculous excuse for a proper release. Or a standard release for Exchange 2013. Does MS realize that these installs aren't destined for a lab? Some of us actually use 2013 in production?

Upgrading 2007 as a "fix" for a 2013 bug is absurd. For one, it's a lot more difficult to update 2007. For two, how about releasing proper code to begin with?

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Hello guys,

I had a problem here in my environment with the installation of CU6 in Exchange Server 2013.

Of the 10 servers that I tried to install 7 servers had the same problem, the qua displays the message "fms is not starting in Exchange Server 2013 SP1".

Anyone here experienced this problem or could tell me how to solve this problem?

Help Please!

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Marcus reported a new issue at my blog -


Exchange 2013 proxy for activesync WILL BREAK for legacy 2007 mailboxes – I am currently working with MS to resolve but so far there is no fix. They have multiple other customers with the same issue.

Please share if you have any update on it

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Safe to say Exchange Server 2013 CU6, is THE WORST CU released for Exchange Server 2013.........TOTAL DISASTER....need to get CU7 out ASAP........please take care of your On-Premises customers.......
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@BrianK2, @PrabhatNigam - We will be publishing KB2997847 later today for the 2007/2013 EAS proxy issue. All customers can now request a combined fix for both 2007/2013 co-existence issues. Both of these fixes will be available in our next cumulative update.

@Renat Matveev - The OWA new mail sound notification is confirmed and will be addressed in a future cumulative update. KB2993499 (not yet published) is tracking this issue.

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I contacted PSS and they were not able to supply KB2997209 hotfix. They informed me that the hotfix has been pulled or that the weekend support staff was accidentally not allowed to access it due to a permission issue. If someone from MS is looking at

this, I have an open case (114082811752158) and please reach out to me if you can supply the hotfix.

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Will MS release CU6v2?
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... and another BUG in CU6:

WebReady Document Preview stopped working in OWA after Exchange server has been upgraded from CU5 to CU6 using Basic or Windows Integrated Authentication method for owa and ecp v-dirs which is a recommendation for eg. UAG or TMG based publishing.

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You guys really underestimate this for use very BIG disadvantage: "Larger update packages". We have 20 on premises Exchange 2013 servers, about 12 of them are connected via vSAT (very slow link). Getting the CU's to those location now have become an almost

impossible process!

- Downloading the large package via vSAT saturates the link to much, so our users will complain a lot.

- Sending it via USB is an option but not always that easy (because some of the locations are Vessels). When the USB arrives with CU6, CU7 or even CU8 is allready available.

- Copying via the network, will also saturate the vSAT too much.

If the updates were small, instead of the complete binaries, just like with Exchange 2010, our update cycle would be way more doable and efficient. Thank you very much for making "servicing Exchange 2013" a very daunting and a nearly impossible task!

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Issue Reported: Ryan reported on my blog that they are facing an issue with CU6 in exchange 2007 mix mode here. Any confirmation will be appreciated.


Following issue reported.


Do not install this CU6 if you have a 2007COEX with EX13. Were having major issues with databases flapping. This is due to EX07 mailboxes talking to EX13 mailboxes. MS are aware of this and working on a fix now.

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Looks like in CU6 still presents string error in mail-enabled Public Folders, tab "mail-flow settings" (Mail-Enabled Public Folder -> Edit -> mail flow settings ).

Default choosen settings is:

Reject messages from: All senders

But it isn't true meaning of string. If we look at Exchange 2007 documentation (

http://technet.microsoft.com/en-us/library/bb629656(v=exchg.80).aspx ), we will see, that correct string is

Reject messages from: No senders

And this is the correct string. It is very confusing, when you see that all Public Folders have enabled option "Refuse all messages from all".

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Ok MS tech just got me the hotfix, installed and testing server now.
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@Aleksey Medvedovskiy

You don't need "Health Manager Microsoft Exchange" on Edge and ADtopology is not there because it is not part of domain. I have answered the same question in my blog here. -


Run this below command on your edge server to get the required services status


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@Aaron Marks - The KB2997209 update has definitely NOT been pulled and we have customer confirmation it resolves the issue. I have confirmed that all the appropriate support individuals should have access. If you are finding that a support individual cannot

assist you, request that your inquiry be escalated.

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@Martijn Westera/@Anon-1 - We have no plans to release a CU6-V2. We are able to address the issue affecting hybrid customers and 2007 co-existence without releasing a new version. We also do not want to disrupt the plans of customers and those who have

already successfully deployed CU6 who do not need either of these capabilities.It's

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OWA sound notifications are NOT fixed. Are Exchange developers and QA are all deaf?


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Good looking out @PrabhatNigam. We were going to install this next week, but I think we'll hold off now.
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And another one

After installing CU6 servers are randomly rebooting from Bugchecks 0x0ef. Related to:

ROCESS_OBJECT: ffffe0007194a080

IMAGE_NAME: wininit.exe


MODULE_NAME: wininit

FAULTING_MODULE: 0000000000000000