Windows Update 2026-05 .NET Framework Security Update (KB5087051) causing printer issues
Posted by No_Blueberry1248@reddit | sysadmin | View on Reddit | 10 comments
Has anyone else had issues with 2026-05 .NET Framework Security Update (KB5087051) causing printing problems? I've had to uninstall the update on several computers but on some just reinstalling the printer/driver resolves the issue.
Only been an issue for computers printing to Kyocera models so far.
Old_Candle_4119@reddit
Glad we're not alone. We've been plagued with printer issues since last Wednesday across 100s of Windows 11 clients and Server 2022 VMs, various different models of printers. Print jobs get stuck in the queue for several minutes and then either print or fail. Hitting TCP/9100 with RAW traffic is also randomly delayed up for several minutes. Interestingly the problem didn't start until Wednesday, which is almost a week after Windows Updates were installed on most of these machines. Difficult to troubleshoot because jobs will randomly work instantly and then same PC will start experiencing the issue again.
Will test uninstalling the patch to see if improvement and report back.
No_Blueberry1248@reddit (OP)
Same behavior for us and started on Wednesday for my environment as well.
ITStril@reddit
Sounds like an issue in combination with e.g a new AV/EDR, when it started so late… What are you using? Did you reboot another time after the patch?
No_Blueberry1248@reddit (OP)
I have a 14 day deferral on updates for these users to try to catch these issues. So, it wasn't late, it started after the update installed and they rebooted.
Yes, I rebooted multiple times after clearing print queues, spool>PRINTERS folder, restarting Print Spooler service, and restarting the copier. To get the print jobs to go through again temporarily.
AV/EDR is Defender
I thought it might have been network issues from UniFi equipment as it had an update right around that time as well but as I mentioned so far it looks like uninstalling that update was the only clear resolution.
ITStril@reddit
I do not really understand the timeline: did you install the updates on Tuesday and the issue started after the next reboot, or did you install the updates and reboot earlier?
No_Blueberry1248@reddit (OP)
It's been 20+ years since I chased my tail on a printing issue like this.
Reinstalled drivers, rebooted network equip, workstations and beat my head against the wall.
Searching online found some similar issues reported recently but mostly around print spooler crashing from updates in January.
Microsoft is making underlying changes that aren't well documented, in support of their push to Windows Protected Printing. Even without enabling the feature I am wondering if it is related to this issue.
No_Blueberry1248@reddit (OP)
The update/reboot happened for most computers having the issue on morning of Wed, 5/27 and the issue started that day.
As another person mentioned, it is somewhat sporadic as the user will work or the print job will go through after 5-10 min or fail entirely. Some will be fine for hours after that or after rebooting computer and copier.
TBH, I am waiting until Monday when more users get back online to see if uninstalling the update truly/fully resolves the issue. I reproduced the issue and "resolved it" on a test box at that location but won't be sure until more users report back.
St0nywall@reddit
Try restarting the print spooler service.
Note: Rebooting the computer isn't the same as restarting the service in this case. Trust me.
No_Blueberry1248@reddit (OP)
Restarting spooler service didn't resolve it. Restarting the copier would sometimes let a couple jobs through but maybe an hour later the same computers would start failing again.
Neuro_88@reddit
Same. Installing the driver for the particular driver helped. Seems to be a bigger problem with Microslop though.