Hi Jopi,
Thanks for the updates.
I totally understand the frustration about the issue.
Since we have a build-in solution to integrate with Office 365 on the Windows Server 2012 Essential, we don’t need to install DirSync in order to sync the users. It may cause issues during the installation if the services are duplicated. Also, as you can see in our DirSync requirements, Windows Server 2012 R2 Essentials is not listed in the requirement table.
For the current issue, can you please let us know how many Domain Controllers are there in your organization? According to my research, multiple DCs in the Windows Server 2012 R2 Essentials domain is currently not supported in Office 365 and the product group is working on it to allow that with a future update.
Also for the integration issue, I have searched the specific error messages and found some workarounds have resolved the issue for some of the customers. please try the following steps:
- Replace the file C:\ProgramData\Microsoft\Windows Server\Data\DevicesInfo.xml with C:\ProgramData\Microsoft\Windows Server\Data\DevicesInfo.xml.bak, reboot the server and check if it works.
- Try disabling IPv6 on the network connection and rebooting the server to check if there are any improvements.