Quick Fix (30 seconds): Restart the App or Service
This error usually means the thread pool couldn't accept a new piece of work because it was overloaded or shut down. The simplest thing to try: close the program that threw the error, wait five seconds, then reopen it. That clears out any stuck threads in that app's pool.
If the error happens in a Windows service—like when you're using a network printer or a scheduled task—restart that service. Open Task Manager (Ctrl+Shift+Esc), go to the Services tab, find the service that matches the app, right-click it, and choose Restart. You'll see the status blink from Running to Stopped, then back to Running.
Still seeing it? Move to the next step.
Moderate Fix (5 minutes): Install Windows Updates
Microsoft has patched thread-pool issues before, especially on Windows 10 21H2 and Windows 11 22H2. Go to Settings → Windows Update → Check for updates. Install any pending updates, then reboot. After the reboot, watch the app that was failing—if it loads without the error, you're done.
Don't skip this because you think updates don't help. I've seen this exact error clear up after a cumulative update for .NET Framework 4.8, so give it a shot.
While you're at it, check for optional updates, too. Go to Settings → Windows Update → Advanced options → Optional updates. If there's a driver update for your chipset or a reliability update, install it. Those often touch the hardware thread pool that feeds Windows.
Advanced Fix (15+ minutes): Adjust Thread Pool and System Settings
If the error keeps coming back, you're dealing with a deeper problem. Here's what I'd check in order, from most likely to least.
1. Check the Windows Event Log for the real culprit
Open Event Viewer (type eventvwr in Start). Look under Windows Logs → Application. Filter by the time the error appeared. You'll often see a related event from .NET Runtime or Application Error that names the specific executable. That tells you what to focus on—maybe it's not the app you think it is.
2. Increase the thread pool minimum (if it's a server app)
If the error comes from a custom application or a server service you run, the thread pool might just be starved. You can set the minimum number of worker threads in the .NET config file. Find the app's config file (for example, MyApp.exe.config) and add this:
<configuration>
<runtime>
<ThreadPool_ThreadMin>4</ThreadPool_ThreadMin>
</runtime>
</configuration>Set the number between 4 and 8. After saving, restart the service. If the error disappears, you've fixed it. This isn't for everyone—most built-in Windows apps won't read this setting—but for custom software it's a lifesaver.
3. Re-register the COM components
CO_E stands for COM error, so a broken COM registration can cause this. Open Command Prompt as administrator and run:
regsvr32 /i vbscript.dll
regsvr32 /i jscript.dllWait for the success dialog for each one, then reboot. This helps if the error appears when a script or Office macro tries to run.
4. Reset the Windows Update components (if updates are also failing)
Sometimes a corrupted Windows Update store messes with everything. If you've also seen update errors, run the DISM and SFC trio:
dism /online /cleanup-image /restorehealth
sfc /scannowLet DISM finish (can take 10–15 minutes), then run SFC. Reboot after each. This repairs system files that might be blocking thread creation.
5. Check memory pressure
When Windows runs low on memory, it rejects new thread pool work before the system crashes. Open Task Manager → Performance → Memory. If Available memory is under 1 GB, close heavy apps (browsers with 50 tabs, video editors) and see if the error stops. Long-term, consider adding RAM if you're constantly below 2 GB free.
When to stop and what's next
If you've tried all of this and the error still appears, it's likely a bug in the specific application, not your system. Check the app's support forums or contact the vendor. Also, check if there's a newer version of the app—developers often fix thread pool issues in patches.
One last thing: make sure your antivirus isn't blocking the app. Add an exclusion for the app's folder (temporarily) and test. Some AV suites interfere with thread creation, especially if they use behavior monitoring. If that's the cause, white-list the app permanently.
The key takeaway: start with the restart, because it's free and fast. Then updates. Then the deeper stuff. You don't need to do everything if the first steps clear it.