O365 - Azure Sync - object deletion limit

[william_tropico]

Morning,

 

Got a strange one. Had an email at 12:15am which said "Identity synchronization object deletion limit reached".

 

I saw this at 5am and panicked! It looks like over 500 items were attempted to be deleted during the sync between AD and O365. I looked in Active directory and looks like everything is still there.

 

What would have caused this and at such a strange time, and how can I see what was removed?

[chazzy2501]

phew, lucky I don't have alerts setup to read at home.

[meldistrict12]

If you have the Synchronization Service Manager - take a look on there, it should show what it was trying to delete.

[MrKJLS]

You can turn off the limit and then do the sync, switch it back on

 

https://docs.microsoft.com/en-us/azure/active-directory/hybrid/how-to-connect-sync-feature-prevent-accidental-deletes

[william_tropico]

going though the logs it looks like devices and not users but why would it suddenly try and remove 500+ computers from Azure? They are still all in AD

[Andycat]

We had that today too

[jdsok]

We also had 800+ objects try to delete out of Azure, when they were still alive and active in our on-prem AD system. I did notice they were all Win7 machines.

[chaplic]

Did azure ad connect update itself? there's a change as to how it decides to sync computer objects if they have a cert (or not)

[jdsok]

Did azure ad connect update itself? there's a change as to how it decides to sync computer objects if they have a cert (or not)

Maybe? Do you have any more information about a change in how it decides to sync computer objects? We have a single on-prem AD domain that we're syncing for hybrid AD join, and as far as I can tell it's just pointed at our computer and user OUs, nothing fancy.

[georgeescott]

Here’s the Microsoft article on it: https://docs.microsoft.com/en-us/azure/active-directory/hybrid/reference-connect-device-disappearance.

 

I suspect you have automatic upgrade enabled on the Azure AD Connect client which kicked off the deletions when it upgraded to 1.4.xx.x.