Jorge's Quest For Knowledge!

All About Identity And Security On-Premises And In The Cloud – It's Just Like An Addiction, The More You Have, The More You Want To Have!

(2017-06-19) Azure AD Connect Health For Sync To The Rescue

Posted by Jorge on 2017-06-19

I was playing around with some Azure AD (AAD) features and I required a new synched account in AAD. So I picked one of my existing accounts in the on-premises AD and added the user account to the groups that allowed it to sync to Azure AD, assign it a license for O365, assign a license for EMS and allow it to use SSPR. Instead of waiting for the next sync cycle I decided to force a delta sync within AAD Connect. So far so good. While AAD Connect was synching I decided to prepare some other things.

To my surprise I saw the following error in AAD Connect


Figure 1: Error In AAD Connect About “AttributeValueMustBeUnique”

Clicking on [Detail] I saw the following details regarding the error


Figure 2: Error Details In AAD Connect About “AttributeValueMustBeUnique”

ERROR = AttributeValueMustBeUnique
Unable to update this object because the following attributes associated with this object have values that may already be associated with another object in your local directory services: [ProxyAddresses SMTP:John.Doe@XXXXX;]. Correct or remove the duplicate values in your local directory. Please refer to for more information on identifying objects with duplicate attribute values.
Tracking Id: xxxxxxxxxxxxxxxxxxxxxxxxxx

This is basically saying there is another object in AAD with the same value of "SMTP:John.Doe@XXXXX" in the proxyAddresses attribute

Now that was weird because the object with UPN ‘John.Doe@XXXXX’ was never synched to AAD as a user. To be sure I checked if there already was a user with the same UPN and/or proxyAddresses. As I expected there was none. I also knew for sure there was no conflicting object in the on-premises AD. Nevertheless I checked it with ADFIND (instead of PowerShell because hadn’t used for quite some time!). And again as expected there was none! So what the heck is going on!?

First I will tell you what was wrong and why, and after that I will guide you through troubleshooting

At this point in time I’m always using AAD Connect to sync stuff from AD to AAD. I also have a MIM Infrastructure using the AAD connector that also syncs stuff from AD to AAD and more specifically users, groups and contacts. However I had not used that for quite some time. What I had forgotten was that in the past I synched my mailbox enabled user accounts to AAD (Office 365) as contacts. So almost all on-premises users exist as contacts in AAD.

Definition of the issue:

The error in figure 2 is misleading as it is telling me to check my on-premises AD to resolve the conflict, but there is NO conflict in my on-premises AD!

Just to be sure I used:

  • ADFIND/PowerShell to query for any object with the same UPN value or the same proxyAddress value – Only 1 object was returned which was expected
  • IDFIX to check for conflicts – No conflicts found for this object in the on-premises AD – This was expected
  • Directory Synchronization Troubleshooter to check for conflicts – No conflicts found for this object in the on-premises AD – This was expected

Now it was time to check AAD. It had to be in AAD somewhere, but what was causing it!? I was looking at all troubleshooting capabilities.

I found the following blog posts that ONLY focus on user accounts in AAD

Looking at the error in figure 2:

  • “ObjectId” contains the objectID of the object I was trying to sync to AAD
  • “ObjectIdInConflict” contains the objectID of the object already in AAD with which the conflict was being caused

Therefore I needed to query AAD using the objectID in “ObjectIdInConflict”. I decided to use the CMDlets in the MSONLINE module

To look for users in AAD with that same objectID, I executed:

Get-MsolUser -ObjectId <objectid value in “ObjectIdInConflict”>

No result

To look for groups in AAD with that same objectID, I executed:

Get-MsolGroup -ObjectId <objectid value in “ObjectIdInConflict”>

No result

I suddenly remembered about my MIM infrastructure and what it was synching, so I decided to also execute:

Get-MsolContact -ObjectId <objectid value in “ObjectIdInConflict”>

Bingo! One object was returned! Yeah!

Now I do not have many objects. Howeverm if you do have many object, this might take quite some time as unfortunately the MSONLINE module does not have a CMDlet like ‘Get-MsolObject’. However, the AzureAD module does have such a CMDlet that allows you to search across object types, being:

Get-AzureADObjectByObjectId -ObjectIds <objectid value in “ObjectIdInConflict”>

Again, Bingo! One object was returned! Yeah!

I also received the following e-mail telling me about the conflict. To be honest, the mail is not really helpful from an informational perspective. It is however from a warning perspective. With the latter I mean it triggers me to go look in Azure AD Connect Health, which will tell me what is wrong and why.


Figure 3: Mail From AAD Telling Me About the Conflict Error

Another option for troubleshooting this is Azure AD Connect Health for Sync. Trust me when I say that Azure AD Connect Health tells what is wrong and why. It showed me the sync error including all the specifics around the error in one view. Really really helpful! Let’s have a look at this!

Go to the Azure AD Portal ( and then go to the Azure AD Connect Health blade. In my case I have Azure AD Connect Health for Sync, ADFS and AD. So should you!. Make it easy on yourself!

Although Azure AD Connect Sync tile so as healthy, to its left, does tell you there is a sync error. Click on that tile.


Figure 4: Azure AD Connect Health In The Azure AD Portal

A new window opens with all the sync errors by type. In this case it is about the “Duplicate Attribute” issue. I clicked on that tile


Figure 5: Azure AD Connect Health For Sync With Errors By Type

A new window opens with all the sync errors about “Duplicate Attributes”. In my case I had and saw an error about a duplicate value in the proxyAddresses attribute. I clicked on the listed object.


Figure 6: Azure AD Connect Health For Sync With A “Duplicate Attribute” Error For An Object

A new window opens with all the details about the “Duplicate Attribute” conflict and the objects involved. At the bottom you can see the conflicting attribute and the conflicting value. Now I know I have to get rid of the contact object to make it possible for the user account in AD to get a corresponding user account in AAD.


Figure 7: Azure AD Connect Health For Sync With “Duplicate Attribute” Error Details

BINGO!!! Smile

Now my suggestion for this is:

  • Make sure to get Azure AD Connect Health up and running
  • As soon as you see an error in AAD Connect (figure 1 and 2) or receive the e-mail (figure 3) about it, make sure to read it carefully. At this point in time I would say to go right away to the Azure AD Connect Health blade in the Azure AD Portal and check there what could be wrong. It is very likely it will tell you what is wrong and why!

Additional information:



This posting is provided "AS IS" with no warranties and confers no rights!
Always evaluate/test everything yourself first before using/implementing this in production!
This is today’s opinion/technology, it might be different tomorrow and will definitely be different in 10 years!
########################### Jorge’s Quest For Knowledge ##########################
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One Response to “(2017-06-19) Azure AD Connect Health For Sync To The Rescue”

  1. said

    Thanks Jorge, another great post 🙂

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