I have Windows 10. A process named "spoolsv.exe", which is the print spooler, takes about 30% of my CPU. Based on other advice from the internet, I tried the following:

  • Based on this answer, I removed all files from the "C:\Windows\System32\Spool\Printers" folder.
  • Based on this link, I ran the Windows troubleshooter on all the printers; no problems were detected. I also verified that all the print queues are empty.
  • I ran a malware check (with "iolo system mechanic").

This did not work. Whenever I stop the service, the CPU relaxes (but I cannot print); when I restart the service, the CPU works hard.

What other options are there?


Sounds like a printer driver issue. As answered in this question, spoolsv.exe loads printer drivers into its process. So if your printer's driver is for an incompatible model or is just buggy/poorly written, it might have issues like hanging threads and/or memory leak, which would lead to high CPU and high RAM usage respectively.

Since you didn't specify the brand and make of your printer, I cannot give specific instructions. But generally those are the steps you want to take:

  1. Identify the offending driver and associated printer. This could be easy if you only have one printer installed on your machine. See * for steps if you have multiple.
  2. Uninstall its drivers by removing the printer in control panel.
  3. Go to the website of your printer's manufacturer, then look for the latest stable driver for the specific model of your printer. Make sure their model numbers are exactly matching - carelessly using drivers for a closely related variant of any device is a common cause for trouble.
  4. If the problem persists with the newest correct drivers then you are unfortunately out of luck. Contact printer manufacturer's support and submit a bug report. Maybe they will update their drivers but honestly, don't expect anything.

*: Go to Control Panel -> Hardware and Sound -> Devices and Printers, then remove printers that you suspect are offending one by one, reboot and check if CPU usage has normalised, repeat if not. Note that you will have to reconfigure the printers you remove afterwards. Also you probably want to leave virtual printers (such as Adobe PDF, Fax, Microsoft Print to PDF, Microsoft XPS Document Writer, etc.) alone as they very rarely cause problems.

This kind of problem is unlikely to be caused by anything other than bad driver. Of course you can try things like reinstalling OS, but unless you have been planning to do so for another reason I wouldn't recommend it. I doubt it's going to fix the problem anyways.

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  • Is it necessary to reboot the computer after each removal of driver, or is it sufficient to just restart the spool service? – Erel Segal-Halevi Feb 26 at 14:59
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    To be completely honest, I'm not sure. Intuitively I feel like simply restarting the service should be enough, but who knows, maybe the printer drivers are loaded by some other services upon boot. I mean, it's not like W10 is opensource. Given that a reboot doesn't take too long to do, if it's up to me, I'd probably just reboot to be safe. – cyqsimon Feb 26 at 15:58
  • I removed some old unused drivers, restarted the system, and so far, the problem is gone! Thank you very much. – Erel Segal-Halevi Mar 5 at 18:59

I looks like the printer driver is having a hard time translating whatever file you throw at it into the printer's native language.

Try e.g. with a plain text file (no Word or anything, plain text, like C source code or something). Try with a simple PDF file (no images, just text).

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  • The problem occurs even when I do not priint anything. I verified that there are no documents at all in all print queues.Then I restarted the service, and in several seconds, it already started grinding. – Erel Segal-Halevi Feb 26 at 13:48
  • @ErelSegal-Halevi borked driver, messed up Windows/Windows bug. See if upgrading driver/updating Windows fixes things. Perhaps look for alternative drivers, check that it is the correct driver for your printer, ... – vonbrand Feb 27 at 1:54

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