If you are having problems with Windows Server 2012 Domain Controllers reboot looping, Microsoft just released a new security update (Jan 11th 2022) that causes those problems.

Here are the steps to uninstall the update:

1. Start your VM in safe mode
2. Uninstall Update Rollup KB5009624
3. Reboot your server
4. (optional) Check if critical services are up and running
5. For the moment disable automatic installation of updates until Microsoft releases a fix

References:

https://www.kiratas.com/security-updates-from-january-2022-with-massive-collateral-damage-in-windows/

If you ever wondered if there is a cooler or faster way to update a computer’s group membership without having to reboot: well there is. If you delete or “purge” the kerberos tickets on the machine and then perform a gpupdate, the client is going to retrieve a new kerberos ticket with the new group membership.

Here are the two (well, if have never heard of gpupdate /force):

klist -lh 0 -li 0x3e7 purge

gpupdate /force

References:

https://www.shellandco.net/update-computer-membership-without-reboot/

On the first day of a new year (for me it was the second day) Microsoft gave us a present to work on that affects Exchange servers. Affected systems could not send or receive mails, messages would get stuck in message queue with the error “Message deferred by categorizer agent”. Here are the two relevant event viewer entries:

The issue here is that the malware filter could not scan the message because of this error (it has to do with date time not fitting into 32 bit integers anymore) and the message would not get sent to the recipient. To temporarily resolve the issue, you can disable antimalware.

Open PowerShell as admin.

& “$env:ExchangeInstallPath\Scripts\Disable-AntimalwareScanning.ps1”

Restart MS Exchange Transport Service

Restart-Service MSExchangeTransport

References:

https://www.itwriting.com/blog/11910-exchange-emails-stuck-in-queue-because-message-deferred-by-categorizer-agent-happy-new-year-admins.html

If you get the error 0x0000011b on Windows 7 and later clients after updating your print server, here is a registry key that might help you:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Print
DWORD RpcAuthnLevelPrivacyEnabled 0

The key needs to be set on your print server. Remember that by setting this key, you will effectively re-open the print nightmare security flaw by downgrading your security level on the server. If you want a persistent fix, you should use type 4 printer drivers, which do not need admin rights on the client side. Admin rights are needed if you have type 3 printer drivers.

References:

https://docs.microsoft.com/en-us/answers/questions/563223/windows-cannot-connect-to-the-printer-error-0x0000.html

Have you ever gotten this annoying error when trying to open old control panel settings from the new settings app? This usually occurs in a domain environment.

You can fix this by creating a Domain policy or locally through secpol.msc > Local Policies > Security Options > User Account Control: Admin Approval Mode for the Built-in Administrator account:

References:

https://martinsblog.dk/windows-server-2016-systemsettingsadminflows-exe-error/