Tasklist shows process but taskkill is unable to kill it, even as admin

I had a similar problem with multiple instances of conhost.exe that I could not terminate with taskkill, even giving the exact pid. I always got the same error, saying that there are no instances of the task.

So I did what Pimp Juice IT suggested in a comment above using the following command, which successfully killed all conhost.exe at once.

wmic process where name="conhost.exe" call terminate

I'm unsure of the actual ramifications of my method on the system but anytime I need to kill a process and am told Access Denied I right click the process, go to properties, the security tab, Advanced, Owner tab, and change the owner from TrustedInstaller to the account I want to kill it from. Haven't encountered anything it didn't work on yet.

If the process was started from Visual Studio, it's possible that the debugger crashed, but VS still somehow has an attachment to the process, keeping it from being able to be killed. Just shutting down Visual Studio will also shut down the rogue process, in this case.