Windows 10 users and administrators are reporting large-scale network printing issues after installing cumulative update KB5006670 and other updates released this week.
Microsoft released Windows updates to fix bugs and security vulnerabilities on Tuesday as part of the October 2021 Patch Tuesday.
These updates include KB5006674 for Windows 11, KB5006670 for Windows 10 2004, 20H1 and 21H1, KB5006667 for Windows 10 1909, and KB5006714 for Windows 8.
Since installing update KB5006670, users report that they cannot print to network print servers, with some users receiving 0x00000709 Where ‘Item not found‘errors when trying to print.
In an eight-page forum topic on BleepingComputer, Windows administrators recounted their frustration with printing bugs and came to the same conclusion: uninstalling this week’s updates fixes the problem.
Since July, Microsoft has been releasing a constant stream of security updates to address PrintNightmare vulnerabilities in the Windows print spooler.
As threat actors, including ransomware gangs, actively exploit these vulnerabilities, Microsoft has dramatically changed its point and print function. Unfortunately, while these changes fix the vulnerabilities, they also cause printing issues on network print servers.
This week, Microsoft released other security updates for Windows printing vulnerabilities tracked as CVE-2021-41332 and CVE-2021-36970, likely causing the new network printing issues.
While most of the reported issues are related to Windows 10 update KB5006670, this is likely due to the fact that it is the most widely used version of Windows right now.
The same security fixes were also released for Windows 10 1909 and Windows 11 and will likely cause similar issues on those versions of Windows.
How to troubleshoot network printing KB5006670
When the September cumulative updates were causing printing problems, they could be resolved by allowing non-administrators to install printer drivers or by disabling the “RpcAuthnLevelPrivacyEnabled” registry value.
However, this registry key no longer works for issues caused by October updates and users need to fix it using other methods.
The BleepingComputer forum topic includes many suggestions from Windows administrators on how to troubleshoot network printing issues caused by Windows 10 update KB5006670. Unfortunately, because these suggestions suppress security updates or don’t always work, they’re not ideal for resolving issues.
What makes these printing problems so frustrating is the lack of clear advice from Microsoft and the many changes that occur every month in the printing function of Windows.
As these changes address all different vulnerable aspects of the Windows print spooler, they create a jumble of individual fixes that Windows administrators need to determine if they will resolve their printing issues.
BleepingComputer has contacted Microsoft for official advice on resolving all of these issues, but has not had a response yet.
Method 1: Uninstall KB5006670 update
The most common suggestion is to simply uninstall the update KB5006670, which can be done using the following command in an elevated command prompt:
wusa /uninstall /kb:5006670However, uninstalling the update will remove security patches for 74 vulnerabilities, including one actively exploited, making this a dangerous method.
Method 2: replace C: Windows System32 Win32spl.dll
Others have found that replacing the Win32spl.dll DLL file with the September 2021 update release would resolve the network printing issue.
“KB5006670 replaces C: Windows System32 Win32spl.dll with version 10.0.19041.1288 which stops printing
We are replacing this dll with version 10.0.19041.1237 which was installed September cumulative update
The attached batch script will copy your “good” dll file to each computer it runs on from a server location and rename the “bad” dll. I run it as a startup script for convenience “
Since this DLL has likely been modified as part of a security update, your computer will also be less protected against possible future vulnerability exploits.
Method 3: Recreate the print queues on the print servers
Some users also reported that removing and reinstalling their printers on the print server resolved their issue.
When you remove the printer and install it again as an administrator, the queues will be rebuilt, potentially allowing printing to work again.
However, workstations may need to be reconfigured to use the new print queue, which can be a very time-consuming task for some organizations.
Method 4: Re-enable the CopyFiles feature
Finally, some HP printer drivers require the CopyFiles feature, which Microsoft turned off by default in September.
For users who still need this feature, Microsoft has introduced a Hidden Group Policy that allows you to turn it back on.
To enable the CopyFiles function, create a Windows registry value under the HKLM Software Policies Microsoft Windows NT Printers named key CopyFilesPolicy. When set to “1”, CopyFiles will be enabled again.
