Sync with on-site Active Directory

Azure AD Connect client service failing to start

Accompanied by an event ID 528 from SQLLocalDB 15.0 in the Application event log with the description:

WaitForMultipleObjects
575
{Application Error}
The application was unable to start correctly (0x%lx). Click OK to close the application.
3714

Identify the account that the ADSync service is running over, and then copy over model.mdf and modellog.ldf from C:\Program Files\Microsoft SQL Server\150\LocalDB\Binn\Templates to %ServiceProfilePath%\AppData\Local\Microsoft\Microsoft SQL Server Local DB\Instances\ADSync2019. Alternatively, the AD Sync Service Repair Powershell script can be used to automate the process.

Update the AD Connect client to a supported version, and run the Azure AD Connect UI to update the synchronisation engine. 

Convert on-site AD objectGUID to Azure AD ImmutableID

Use the below Powershell command to convert the ImmutableID within Azure Active Directory to the objectGUID in the on-site Active Directory

[Convert]::ToBase64String([guid]::New("InsertGUID").ToByteArray())

Convert Azure AD ImmutableID to on-site AD objectGUID

Use the below Powershell command to convert the objectGUID from the on-site Active Directory account to the ImmutableID format used in Azure Active Directory.

[Guid]([Convert]::FromBase64String("ImmutableID"))