Windows Updates released in September 2025 are causing authentication failures between computers. The following updates have been identified as affected: KB5064081, KB5065426 and KB5065429.

Any Windows feature requiring computer-to-computer authentication may be affected, including:

• Network browsing between computers

• Printing to shared printers via another computer (direct printing to network printers is not affected)

• Launching Toniq on workstations if the Toniq server is impacted

Cause

It has been determined that authentication failures are occurring on networks where computers have been imaged from the same source machine.

Imaging is a method commonly used by computer hardware companies to speed up the setup process by copying a single machine’s hard drive to multiple computers with similar hardware. This approach allows IT technicians to avoid performing a full installation of Windows and its updates on each device, as the source disk already contains the necessary configuration.

However, the cloning process also copies the Computer Security ID (SID), resulting in multiple computers sharing the same SID if it is not reset before cloning. Although a process exists to remove the SID before imaging, till now it has often been considered unnecessary, even by companies closely associated with Microsoft.

Following the installation of the latest Windows Updates, communication between computers imaged from the same source is blocked. When two computers with identical SIDs attempt to authenticate, the process fails because each computer cannot verify the other’s identity. Essentially, each computer says, “You’re pretending to be me. I’m not going to let you in because I don’t believe that you are who you say you are.”

Resolution

In working with Toniq and other companies such as ours, we have identified a method to resolve this issue and renew the SID so there will be no conflicts. However this requires time remotely on each PC. IN the meantime we have suspended the installation of the offending updates so we have more time to effect the repairs to your computers.

If you have any questions please feel free to call on 029 874 5649