Microsoft says Windows clients are experiencing network printing issues after installing Windows 11 KB5006674 and Windows 10 KB5006670 updates released with this month’s patch on Tuesday, October 12.
Users attempting to connect to shared printers on Windows print servers may encounter several errors preventing them from printing over the network.
Errors that Windows print clients will encounter after deploying KB5006674 include:
- 0x000006e4 (RPC_S_CANNOT_SUPPORT)
- 0x0000007c (ERROR_INVALID_LEVEL)
- 0x00000709 (ERROR_INVALID_PRINTER_NAME)
The full list of Windows platforms affected by this issue includes:
- Client: Windows 11, version 21H2; Windows 10, version 21H1; Windows 10, version 20H2; Windows 10, version 2004; Windows 10, version 1909; Windows 10, version 1809; Windows 10 Enterprise LTSC 2019; Windows 10, version 1607; Windows 8.1; Windows 7 SP1
- Server: Windows Server 2022; Windows Server, version 20H2; Windows Server, version 2004; Windows Server, version 1909; Windows Server, version 1809; Windows Server 2008 SP2
As Redmond explains, this known issue affecting printing on Windows client and server platforms is specific to print servers more commonly found in enterprise environments.
Microsoft said it is working on a solution to allow print clients to establish RPC packet privacy connections to Windows print servers using RPC over SMB.
Users experiencing printing issues in the past two weeks
Windows 10 administrators and users have been reporting large-scale network printing issues in a 14-page forum topic on BleepingComputer in the past two weeks since the October Patch Tuesday updates were released.
While recounting their frustration and attempts to address the printing bugs, they came to the same conclusion: uninstalling the October Cumulative Updates resolves the printing issue.
Since then, the problems have gotten so bad that Windows administrators have resorted to replacing Windows DLLs with older versions to re-enable printing.
The DLLs that administrators replace to fix printing are localspl.dll, win32spl.dll, and spoolsv.exe.
While this approach removes patches for print spooler vulnerabilities, it avoids uninstalling cumulative updates, which would remove all October security updates in the process.
Microsoft offers a workaround
Customers affected by these printing issues can now use an official workaround provided by Microsoft to resolve the issue.
The steps should be performed ONLY on affected print servers that meet the following prerequisite: “print clients must have installed a Windows update released in January 2021 or later before the print server has installed” the October 2021 updates.
If the workaround requirements are met, Microsoft asks customers to “ensure that network security and VPN solutions allow print clients to establish RPC over TCP connections to the print server on the following port range:”
- Default boot port: 49152
- Default end port: 65535
- Port range: 16,384 ports
Redmond also provides the following articles for additional guidance:
Prior to disclosing this new issue, Microsoft said it fixed other known Windows 11 issues causing printer installation failures and prompts for administrator credentials before each attempt to print in corporate environments.
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