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For some reason I can't end any processes in Task Manager; I get an access denied error.

I am on an administrator account, and the processes I'm trying to terminate are not vital - e.g. even if I open Notepad I'm not able to end it.

I used to be able to do this without any issues but something must have happened recently that now prevents me from doing so. Any ideas how to fix this?

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Try starting up process explorer, "find..find handle" enter the name of any process, see if there's something they all have in common that is locking them. i'm not sure how that'd work 'cos normally it's a file that is getting locked by a process, but try it. What's the -full- error message? Also, try taskkill /f /im processname.exe And if it gives you an error, what is that error? – barlop Jul 20 '11 at 4:17
Formatting a disc volume is not a catch-all answer to everything, and shouldn't be thought of as such. Report, in your question, what user account Task Manager itself says you are running the Task Manager process under the aegis of. And report what user accounts the processes that you are trying to terminate are running under the aegis of. – JdeBP Jul 20 '11 at 11:39
There is only one account on the system, which is mine and it's the admin account, as for the process, for testing purposes im just opening notepad and trying to end it but getting the access is denied error which is very weird. – Mankind1023 Jul 20 '11 at 13:58
You haven't done as asked. Do what was asked. There is not only one account on any Windows NT system. – JdeBP Jul 20 '11 at 23:52
@Gareth your edit , removing the last line, removed some evidence of the OP's incompetence that was worth knowing about. – barlop Jul 21 '11 at 1:58

For a short term answer, this Microsoft KB might be of use: Cannot End Service Processes with Task Manager. Basically it boils down to using the taskkill/kill command at the prompt.

Does the problem persist after a restart?

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Yes it does, restarting didn't solve the issue. – Mankind1023 Jul 20 '11 at 13:58

I figured out the problem: I use Comodo Antivirus, and somehow a setting for Defense+ changed. It's on safe mode (as always), and used to work fine, but when I disabled it everything started functioning correctly again. I have to go through the program to see what exactly happened since at first glance everything looks correct, but at least now I know the cause.

It seems very silly since this is something I have customized and have been using for years - I hadn't considered it could be the cause of the problem!

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Glad it got fixed! – surfasb Jul 20 '11 at 18:51

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