[Aditya Sripathi]

Literally just figured this out. I have a Samsung Ativ Book 9 (i7), and since the update with Cortana, the fan has been revving up and down constantly - every second it goes from 50% to 100% fan speed when usually the fan doesn't come on at all, and if it does it comes on at about 30% speed for two or three seconds and turns off... Anyways, uninstalled just about everything because it was driving me mad, and disabled literally everything I can think of, still did it from the moment I turned the computer on and even before I signed in. Found the culprit:

CORTANA. And it didn't work just to turn her off in the settings... Because she was still running under task manager, what I did was fiddle with the security settings to take ownership and set permissions to modify files under Cortana's file location, and I renamed the 'core' dll so that it wouldn't function. As soon as I did that, fan turned off, and after I restarted it now works as before.

I'm extremely relieved. Hope this helps people reading this too, because I haven't seen any proper write ups on this save for one other person on another forum which gave me the idea.

This works! Please repost this on all websites. Thank You so much.

[hypochondrius]

Thanks. So what is the dll file name, and where is it exactly?

This was a bit more complicated than I anticipated. I'm posting this in case others had the same issue with file permissions.

1. Launch Command Prompt (Admin).
2. cd to C:\Windows\SystemApps\Microsoft.Windows.Cortana_<whateveritisonyourmachine>
3. Type and hit Enter: takeown /f Cortana.Core.dll
4. Type and hit Enter: icacls "Cortana.Core.dll" /grant <whateveryourWindowsusernameis>:F
5. Type and hit Enter: rename Cortana.Core.dll Cortana.Core.dly (or whatever extension you prefer to use).
6. Open Task Manager once you have renamed the dll file above.
7. Under Processes tab, look for "Cortana".
8. Right-click and "End Task."

I hope this helps. I just disabled Cortana. I'm not sure if it's solved my cooling fan constantly revving up and down problem yet (ThinkPad Yoga 14 / Lenovo). I did not have this issue until upgrading to Windows 10. Such a pain.

[Marianne Kipper]

I am having the same problem. My Lenovo ThinkPad T520 is somewhat hot in the top left corner, but the task manager says the computer is idle.
What to do?

[dsignori]

This was a bit more complicated than I anticipated. I'm posting this in case others had the same issue with file permissions.

1. Launch Command Prompt (Admin).
2. cd to C:\Windows\SystemApps\Microsoft.Windows.Cortana_<whateveritisonyourmachine>
3. Type and hit Enter: takeown /f Cortana.Core.dll
4. Type and hit Enter: icacls "Cortana.Core.dll" /grant <whateveryourWindowsusernameis>:F
5. Type and hit Enter: rename Cortana.Core.dll Cortana.Core.dly (or whatever extension you prefer to use).
6. Open Task Manager once you have renamed the dll file above.
7. Under Processes tab, look for "Cortana".
8. Right-click and "End Task."

I hope this helps. I just disabled Cortana. I'm not sure if it's solved my cooling fan constantly revving up and down problem yet (ThinkPad Yoga 14 / Lenovo). I did not have this issue until upgrading to Windows 10. Such a pain.

Thanks. But I tried this and no luck for me. Cortana was disabled , but the fan is still roaring... :-\

[hacer619]

My acer aspire laptop cpu fan has been running at full speed for a while. I have been looking at forums of this specific problem and none of the solutions fixed it. I didnt have tasks running in the background. I even reinstalled windows 10 with no luck. Until I found that the fan was even running at full speed in bios menu. So I opened my laptop and disconnected and reconnected the cmos battery. Now the fan is running normal. I hope this helps.

[Michel MrPatton]

Mine is doing this today too. I installed Windows 10 yesterday. It ran OK yesterday, then this morning the fan won't stop. It is ridiculous. I have a Alienware Desktop. Ran fine on Win 7, ran fine yesterday on Windows 10, today the fan will not stop. There are lots of complaints about this, I really hope this is fixed soon.

my alienware desktop does the same thing after updating wndows 10.
the strange thing is that the fans speed up when i power on my desktop, and it stays that way.
i changed the fanspeed controls from automatic to manual in the alienware thermal control, and that settled it down when windows is running, but it is still going crazy on startup. wich it never did on windows 7. and the bios has no fanspeed options.
it might be the standard overclocking tool in Bios, i have to check that out later..

[dsignori]

my alienware desktop does the same thing after updating wndows 10.
the strange thing is that the fans speed up when i power on my desktop, and it stays that way.
i changed the fanspeed controls from automatic to manual in the alienware thermal control, and that settled it down when windows is running, but it is still going crazy on startup. wich it never did on windows 7. and the bios has no fanspeed options.
it might be the standard overclocking tool in Bios, i have to check that out later..

Thanks so much for this. It worked for me too. That's why I love the forums. Thanks!