SSL 3.0 enabled after an Exchange update – Fixed in 2013 CU13

If you have been vigilant, you disabled SSL 3.0 a long time ago on your servers. You may be surprised to find it enabled again after you apply an Exchange Update.

NOTE: This appears to be fixed in CU13 for Exchange 2013. You should still verify after applying any CU however!

From the CU13 setup log:


New-Item -path $keyPathRoot”\SSL 3.0″ -ItemType key -Name “Server” -Force;
Set-ItemProperty -path $keyPath -name “Enabled” -value 0x0 -Type DWORD -Force;




Now, back to the original issue:

A little history: SSL 3.0 has some well-documented security issues and with a reg tweak and reboot, it’s no longer advertised. You can easily test this with my favorite “sanity-check” site:



Enter the server name and click “Check for common vulnerabilities”.

Hopefully it shows green:



Until you apply an Exchange update. So on goes 2013 CU12 for example, and like all good admins you check the certificate one more time against



Well, luckily it’s easy enough to fix of course. Reapply that registry setting and reboot.

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server]


Whew. So, what’s going on here? Well, take a look at the ExchangeSetup.log file under the ExchangeSetupLogs directory at the root of the system drive:


04/26/2016 17:27:46.0177] [1] Executing:
$keyPathRoot = “HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols”;
$keyPath = $keyPathRoot + “\SSL 2.0\Server”;
if (!(Test-Path $keyPath))
New-Item -path $keyPathRoot”\SSL 2.0″ -ItemType key -Name “Server” -Force;
Set-ItemProperty -path $keyPath -name “Enabled” -value 0x0 -Type DWORD -Force;

$keyPath = $keyPathRoot + “\SSL 3.0\Server”;
if (!(Test-Path $keyPath))
New-Item -path $keyPathRoot”\SSL 3.0″ -ItemType key -Name “Server” -Force;
Set-ItemProperty -path $keyPath -name “Enabled” -value 0x1 -Type DWORD -Force;

As you can see, Exchange Setup happily sets that key and enables SSL 3.0.

Just something to put on your post upgrade checklist!


Error when accessing a resource mailbox: “The value ” is already present in the collection”

When accessing a resource mailbox in Exchange 2013 EAC, you may encounter an error that you prevents you from viewing or editing the room mailbox properties:



Powershell is no good either!


Get-CalendarProcessing <Room>
WARNING: An unexpected error has occurred and a Watson dump is being generated: The value ” is already present in the
The value ” is already present in the collection.
    + CategoryInfo          : NotSpecified: (:) [Get-CalendarProcessing], InvalidOperationException
    + FullyQualifiedErrorId : System.InvalidOperationException,Microsoft.Exchange.Management.StoreTasks.GetCalendarProcessing


Cause: Typically this is because there is a disabled mailbox listed in the RequestInPolicy or BookInPolicy attributes for the room.

Solution: Run the following in Exchange Powershell to clear the values. Example:  Set-CalendarProcessing <Room> -BookInPolicy $null  

Once done, you should be able to access the room via Powershell or EAC and re-add any required requesters to the room policy. Alternatively, if you have Exchange 2010 still around, you can simply remove the disabled mailbox via the 2010 EMC.


The Trinity of Email Protection: Lessons Learned using DMARC, DKIM and SPF in Office 365

I am a big fan of DMARC and its ability to easily determine which messages sent as, and from, your SMTP domains are using authenticated and authorized servers. The A in DMARC actually stands for “authentication”, but it’s really a little of both.

Regardless, it’s something I highly recommend and if you are using Office365/EOP, there is really no reason you should not be using it, after all it’s already enabled. In fact, if you choose not to set up any of the email protection trinity, EOP will absolutely mark any message sent from the internet as your domain to your domain as SPAM.

Since you are reading this, I assume you are using it or wanting to use it. To that end, here are some tips and lessons learned from my own experiences:

  1. Start small.  Your first DMARC record in DNS ( should do nothing but report. At its very minimum, it should look like this: “v=DMARC1; p=none;;”  All this does is tell recipient servers that they should send DMARC failure reports to ( This could be a mail-enabled Public Folder).  The p=none does not affect the way messages are delivered. With p=none, you are not suggesting to a recipients mail server that they change the way they handle the messages that fail DMARC checks.  I would recommend you always use p=none, unless you have no 3rd party vendors that send mail as your SMTP domain. In that case, p=quarantine is probably worthwhile once you have vetted out your DMARC policy sufficiently. I would never use p=reject  – unlike a few ISPs out there.
  2. Get your SPF records in order. If you have 3rd party vendors that send as you, this is especially important. It doesn’t take much to exceed the 10 Lookup Max on SPF records. Heck, if you are using EOP, requires three lookups alone! Exceeding that amount can cause failures because recipient domains may ignore your SPF completely.
  3. Don’t forget DKIM! SPF seems to get all the attention, but setting up DKIM could not be easier in Office 365. You can even configure it in the portal now under the Protection menu in EAC. And once setup, there is nothing cooler than seeing that DKIM-Signature in the headers.
  4. There are options if you simply can not get those SPF lookups below 10. The SPF RFC supports macros. Mind. Blown. No really. Imagine a SPF record of “ IN TXT “v=spf1 include:%{i}._ip.{%h}._ehlo.{%d} –all”.  Ok, I am not aware of anyone that does this, but it’s a possibility. Another option is not use SPF records and depend on the DKIM record. This is great if you have no or cooperative 3rd party vendors that send as your domain. DKIM is not limited to that pesky 10 max record lookup and as mentioned above, DMARC messages need to pass either the DKIM or SPF and, not both. If you support multiple SMTP domains, you may want to also consider setting up distinct SPF records for each zone rather then using the include option to keep each domain under that 10 limit.
  5. Don’t forget the alignment requirement! As mentioned above, DMARC will check the sender’s valid SPF or DKIM records in DNS. If one or both of those exist and pass, then alignment must pass as well. This is the magic sauce in DMARC. Alignment simply means the header FROM: matches the Domain “from” (i.e. the MAIL FROM: /Return-PATH) of the message. This is an important consideration because even if the message passes the SPF or DKIM check, it can still fail DMARC if for some reason you have processes that set the FROM: in the header to a completely different domain from the RETURN-PATH or MAIL FROM:. I have seen it happen!
  6. Leverage DMARC inbound. The value-add for DMARC is pretty obvious for messages sent out from your org. But the really cool part is using it inbound to stop those endless spoofing attempts without the need for clunky transport rules. You can create nifty rules to check for failures as illustrated in a previous blog post. This is another reason you want those SPF records to be below 10 lookups. If they exceed allowed amount, you may find that your inbound rules do not correctly detect the dmarc=fail or dmarc=pass.
  7. Whitelisting is your friend. If you are going to create inbound DMARC rules, it is very important to remember that SPF lists mail servers that are authorized to send messages on behalf of your SMTP domain. That’s not necessarily the same list of IPs that will sending as your domain directly to internal users. If you are using WorkDay, SalesForce or any of the multitude of SAAS cloud vendors, you can be pretty darn sure they are sending spoofed messages to your domain, but not to external recipients as you,  so they wont be listed in your SPF. Any whitelisting rules MUST be above the DMARC rule. Seems obvious, but don’t overlook it!
  8. Add a check for dmarc=temperror in your inbound transport rule. If the domain in the Mail FROM: doesn’t exist, you may see a spf=temperror or dmarc=temperror in the Authentication-Results header of the message. If your rule isn’t testing on that, it could slip past your defenses. I have actually seen a number of these from images spun up in 3rd party hosted solutions. I prefer to tag these as FAILs, but that is up to you if you want to let them pass.
  9. Set the inbound rule to only notify you initially. As with DMARC in general, start small. Don’t block anything until you feel confident that only the truly unwanted spoofed messages are trapped. Your initial rule should simply check for a DMARC failure, and send an incident report to a mailbox that you monitor. An example rule is found here. And that leads me to the next tip once you ready to take action on DMARC failures.
  10. Quarantine the message, do not simply set it to a high SCL. You really have two options  ( I would not delete the message) on how to deal with illegitimate spoofed mail, you can force it the quarantine, or set it at a SCL high enough to mark it as SPAM. I recommend forcing it the quarantine so that end-user safe sender lists can not trump your rule.  If you have a user that has added a GAL object to their contacts ( A very common scenario), and has also checked “Also trust e-mail from my contacts” in Safe Senders, the spoofing rule will be defeated.
  11. Add a custom x-header to your rule. This helps you, the help desk and the end-user easily identify why this message was quarantined.

So there are some tips. This is by no means a comprehensive list. I plan to add more or revise these as time permits. If you want to read more, including how to setup DKIM in Office 365,  I would suggest following the blogs of Terry Zink  and Andrew Stobart.



You are unable to choose the OU in EAC when creating a new Mailbox or Groups…

If you have more than 500 Organization Units in your AD forest, you…you will, run into this issue in the Exchange 2013 EAC when creating a new mailbox or group and want to create the object in a different OU other than the default “Users” container.

Upon accessing the OU Dialog box:



You will see this lovely message:


Unfortunately, this is a known issue. There is no fix yet.

I would recommend you simply create the mailboxes and groups in Powershell if you want to specify the OU.

The work-around for EAC:

  •  Edit the web.config file on the MAILBOX server under

     \\Program Files \ Microsoft \ Exchange Server \ V15 \ ClientAccess \ ecp \

    add the following under the appsettings section of the file.

    <add key=”GetListDefaultResultSize” value=”<number more than OUs in your forest” />

Recycle ECP app pool.

Note that you will need to do this after each Cumulative Update.


P.S. If you do not know how many OUs your forest has:

Get-OrganizationalUnit -ResultSize unlimited | Measure-Object

How to create an Outlook Profile for a Hidden Mailbox

Suppose you wanted to create an Outlook profile for a hidden mailbox and, for whatever reason, you do not want to unhide it from the Address Book just long enough to create it. All hope is not lost! ( Unless you are using Outlook 2016). You can do it using the LegacyExchangeDN.

1. Use adsiedit or your favorite LDP viewer/query tool and copy the LegacyExchangeDN of the hidden mailbox. ( I still prefer adfind to this day).

The LegacyExchangeDN value is a property of the user’s object in AD and will be in the form of:  /o=Contoso/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=UserA

2. Create the Outlook profile. It will fail and you will be at the dialog box that shows server name and the users’ mailbox.


3. Remove the “=SMTP:”  value of the  “Mailbox:” and paste the LegacyExchangeDN value you copied from Step1.


4. Hit Check Name and it should resolve and allow you to create the profile and access the mailbox.


This is with Exchange/Outlook 2013. This does not work with Outlook 2016 from what I have seen:




On-Premises Mailbox Missing Retention Policy Tags after enabling Archive in Office 365

Consider the following scenario:

You have an on-prem mailbox, but decide to move your online archives to Office 365 to take advantage of the “Unlimited” storage. No problem. That works great for existing mailboxes, but when creating new archives in the cloud, you discover that the policy retention tags are not surfaced to the end-user in Outlook and the ability to archive to a pst remains.


You have a few options:

Run: Start-ManagedFolderAssistant <user>

If that doesn’t work, move the online back on-premises and run Start-ManagedFolderAssistant.  Alternatively, if the archive is unused, disable it, re-enable on-prem  ( and run Start-ManagedFolderAssistant to speed things up). Once the policy tags appear, move it back to Office 365.

P.S. Ensure you have imported all the on-premises tags to Office 365 per the link below. Otherwise the automatic archiving will not work!






Outlook Error: Remote Server returned ‘554 5.6.0 STOREDRV.Submit.Exception ! – FIXED

UPDATE: It appears that this is fixed in Exchange 2013 CU13:


Full NDR:

Remote Server returned ‘554 5.6.0 STOREDRV.Submit.Exception:TextConvertersException; Failed to process message due to a permanent exception with message data truncated TextConvertersException: data truncated’

This is not a common problem, but crops up occasionally.

If you see this message bounce back when responding to a meeting invitation, try the following:

  1. Set your Outlook profile to cache mode/ Create a new Outlook profile.
  2. Disable any 3rd party add-ins and/or anti-virus.

From what I have seen, switching to cache mode always fixes this.

<Rant>Cache mode is actually the default and preferred mode. Online mode is only recommended in certain scenarios such as a kiosk or regulated environment that forbids a local cached copy of the mailbox. There is no real advantage to online mode. </End Rant>

As to why this happens? Hard to say, but while you are at it, make sure you are running the latest Outlook build. Or use OWA? 🙂


On-Premises mail-enabled Modern Public Folders are not visible in the GAL from Office 365 Mailboxes

Just a reminder. If you are in hybrid mode and using public folders on-premises, the mail-enabled PFs will *not* be visible via the Outlook Address Book for 365 mailboxes – even if they are not hidden from the GAL. All you will see is:


This also means the display name will not be resolvable when creating or receiving a message from the folder.

One work-around is described here under the section “Configure Directory Synchronization” that allows you to create mail-enabled contacts in 365 that represent the PFs.

In the meantime, you will have to wait for one of two solutions:

  1. True mail-enabled PF synchronization.
  2. Supported Modern Public Folder Migration to Office 365. ( Yea, that’s right  – The migration of 2013/2016 Public Folders to Office 365 is not supported right now.




I can’t disable a resource mailbox? Sez Who?

Well, according to you can not.

Mailbox type Disable? Delete?
Archive mailbox Yes No *
Linked mailbox Yes Yes
Resource mailbox (Room or Equipment) No Yes

If you use PowerShell, you most definitely can!

PS C:\temp> get-mailbox TestRoom |FL *rec*
RecipientType                : UserMailbox
RecipientTypeDetails         : RoomMailbox

PS C:\temp> Disable-Mailbox TestRoom

Are you sure you want to perform this action?
Disabling mailbox “TestRoom” will remove the Exchange properties from the Active Directory user object and mark the
mailbox in the database for removal. If the mailbox has an archive or remote archive, the archive will also be marked
for removal. In the case of remote archives, this action is permanent. You can’t reconnect this user to the remote
archive again.
[Y] Yes  [A] Yes to All  [N] No  [L] No to All  [?] Help (default is “Y”): Y


What you can not do is disable a resource mailbox via EAC. The disable option simply isn’t there for some reason. Seems like an odd oversight.



Do I have to be on the latest Exchange Cumulative Update to be supported?

I can’t tell you how many times I have admonished posters in the forums about not being on the latest Cumulative Update (CU) for Exchange 2013. After all, it has all the latest fixes and you want to be supported right?

It’s generally good advice, but is one really not supported if not on the latest and greatest? Yes and No.

When the original 2013 Servicing Model was announced back in, well, 2013, the support requirements were pretty clear:

Q: How long is a CU supported?

A: A CU will be supported for a period of three (3) months after the release date of the next CU. For example, if CU1 is released on 3/1 and CU2 is released on 6/1, CU1 support will end on 9/1.

This was met with some resistance as many on-premises orgs worried about the cadence schedule and their ability to keep up and still allow for proper testing, roll-out etc… Paul lays this out much better than I could here.

As Paul mentions in his post, Microsoft will not simply turn you away if are running an older CU, though they may suggest you upgrade.

But where is that actually officially stated for all the world to see?  It was some time ago beginning with the release of CU2 in July of 2013 and linked in TechNet:

In the new Exchange servicing model customers will continue to receive assistance from Microsoft Support for the lifecycle of the Exchange server product – a customer is not required to be at the most current CU to receive assistance. There are two scenarios that we would like to clarify though:

  1. If during the course of a support incident it is determined that the solution is available in a published CU (e.g., CU2), the customer will be required to install the update that contains the fix. We will not be building a new fix to run on top of a CU published earlier (e.g., CU1).
  2. If during the course of a support incident it is determined that you have discovered a new problem for which we confirm a fix is required, that fix will be published in a future CU that you can then install to correct the problem reported.

Note an important exception:

You will see this blurb on every CU release:

“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., 2013 CU15, 2016 CU4) or the prior (e.g., 2013 CU14, 2016 CU3) Cumulative Update release.”


Maybe you already knew this. But it’s a reminder to myself to always qualify my answer when I tell a forum poster they need to be on the latest CU “to be supported”!