Azure Active Directory Connect - OU Filtering not working as intended

I have recently encountered an Azure AD Connect sync engine that refuses to respect the recent changes to exclude an OU that was previously included.

Azure AD Connect version in question is 1.1.130.0 - April 2016

If you are wondering how to exclude OUs, go to Synchronization Service > Connectors > pick your Active Directory connector > Properties > Configure Directory Partitions > Containers button > enter your Azure AD Connect service account password:

You then wait for the next sync cycle or manually force the sync cycle, and yet you noticed that the objects are not being disconnected from the metaverse, and continue to sync to Azure AD.

To fix this, simply restart the "Microsoft Azure AD Sync" service and wait for the next sync cycle.

Bonus tip:

A grey box with a tick = objects in that OU (not the sub OU) will be synced:

A grey box (without a tick) = objects in that OU will not be synced, but some sub-OUs are selected for sync.

Determine the Azure AD Connect Installation File Version

Sometimes you want to use an older AADConnect installation file for some reason (usually due to a broken update), and you would want to know the version *before* installing it.

The easiest way to find out is to use 7-Zip to open up the MSI file, expand media1.cab file, and extract the file "Microsoft_Azure_ActiveDirectory_Synchronization_Setup_dll".

Rename it to "Microsoft_Azure_ActiveDirectory_Synchronization_Setup_dll.dll" and right click on the file, Properties and then Details tab:

In my case, it's version 1.0.9131, released in December 2015.

You can get the full version history for Azure AD Connect here:

https://azure.microsoft.com/en-us/documentation/articles/active-directory-aadconnect-version-history/

Bonus tip! To manually force a sync using AADConnect 1.1, run the following PowerShell cmdlets:

Full Sync: 

Start-ADSyncSyncCycle -PolicyType Initial

Delta Sync:

Start-ADSyncSyncCycle -PolicyType Delta

Source: https://azure.microsoft.com/en-us/documentation/articles/active-directory-aadconnectsync-feature-scheduler/