AADSync installed on a domain controller running as “Auto-generated standalone Managed Service Account”

Domain controller was rebooted as part of another task then “Microsoft Azure AD Sync” couldn’t start.

Searching for the above error, no solution except reinstalling, but unfortunately no configuration details to replicate. Repair also did not fix the issue.

Digging deeper in application logs, noticed SQL errors which turned out to be the cause

SOLUTION:

Replace two files, model.mdf and modellog.ldf.

Copy from: C:\Program Files\Microsoft SQL Server\150\LocalDB\Binn\Templates

Copy to: C:\Users\ADSyncxxxxx$\AppData\Local\Microsoft\Microsoft SQL Server Local DB\Instances\ADSync2019

Or

Copy to: C:\Windows\ServiceProfiles\ADSync\AppData\Local\Microsoft\Microsoft SQL Server Local DB\Instances\ADSync2019

Destination varies according to installed version.