NEPKernel.sys
NEPKernel.sys is a kernel driver from the anti-cheat that comes with Aniimo's PC version. A file called NEP2.dll comes with it too. Leave it alone while you play. Windows Security can list it as an incompatible driver under Core isolation, which stops Memory Integrity from turning on. To clear it, uninstall Aniimo and delete any Aniimo folder left in your game library. Then restart, and try Memory Integrity again.
What NEPKernel.sys is
It's a kernel driver. That's a program that runs at the deepest level of Windows, like most PC anti-cheat does. It comes with Aniimo's PC version, in the game's own folder. NEP2.dll comes with it too, and that file loads into the game while you play.
Other games use the same anti-cheat too. So if Aniimo has never been installed on your PC, NEPKernel.sys came from something else.
Why Windows flags it
Memory Integrity is under Windows Security, Device security, Core isolation. It won't turn on while an incompatible driver is installed. It can name NEPKernel.sys as that driver. Don't worry, nothing is wrong with your PC. The two just don't run together.
Remove it after uninstalling Aniimo
- Uninstall Aniimo from Steam, the Epic Games Store or the Xbox PC app.
- Open your game library folder and delete any Aniimo folder that's left. Watch out: on Steam, uninstalling can leave the folder behind, with NEPKernel.sys still in it.
- Restart your PC.
- Open Windows Security, then Device security, then Core isolation, and turn Memory Integrity on.
- Does Windows still name NEPKernel.sys? Then find out what owns it. Microsoft's free Autoruns tool shows every driver, its publisher and its location on the Drivers tab. Uninstall the program it belongs to, then restart.
Uninstall Aniimo before you remove anything. When you can, uninstall the program a driver belongs to. That's better than deleting the driver file by hand.
Not confirmed yet
- Whether the driver is ever registered as a service on every install, or only on some.
- Which anti-cheat company makes it.
- Whether the game still runs if you remove only NEPKernel.sys.
NEPKernel.sys, answered
What is NEPKernel.sys?
It's a kernel driver from the anti-cheat that Aniimo's PC version uses. It comes with the game, along with NEP2.dll.
Is NEPKernel.sys a virus?
No. It's a signed anti-cheat driver that comes with Aniimo on PC. Like most kernel anti-cheat, it runs at a deep level of Windows. That's why some players remove it once they stop playing.
Why can't I turn on Memory Integrity?
Windows has found an incompatible driver, such as NEPKernel.sys. To fix it, uninstall the game it belongs to and delete any leftover game folder. Then restart, and turn Memory Integrity on again.
Does NEPKernel.sys stay after uninstalling Aniimo?
It can. If you uninstall through Steam, the Aniimo folder can stay behind with NEPKernel.sys in it. Delete the leftover folder and restart.
Does Aniimo use kernel anti-cheat?
Yes, on PC. The PC version comes with a kernel driver, NEPKernel.sys. It also comes with NEP2.dll, which loads into the game while you play.
Sources: Steam and learn.microsoft.com.