If you're unable to kill a process on your device, getting a message like "Unable to Terminate Process Access is Denied" or the equivalent, you may need to kill the process using another account, such as an administrator account. If that fails as well, you can try to reboot the machine as a last resort to stop the process.
End Process With Access Denied
If you're on Microsoft Windows and getting an "access denied" error when trying to terminate a running application in the Windows Task Manager, you may still be able to kill the process using a different user account. If you're not the user who started the process, you often don't have the right to stop it.
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If you're using a multiuser machine, you may want to check to see who started the process and ask that person to end it. That way you can make sure that you're not interfering with somebody else's work when you end the process.
If you're the only user on the machine, or you're confident the process isn't doing anything useful for anyone else, you can use an administrator account to end the process. To do so, you must have the administrator password on the computer. If you're using a corporate machine, you may need to ask your IT department or the equivalent for help.
Using an Administrator Account
To use an administrator account to end the process, you can either log into the system using an account with administrator privileges or open the command line using an administrator password while staying logged in to another account.
To log in as an administrator, first log out from your normal account. In Windows 10 or Windows 8, do this by clicking the "Start Menu" and then clicking your username and choosing the "Sign Out" button. In older versions of Windows, click the "Shut Down" button within the "Start Menu" and then choose the "Log Out" option.
Once you're logged out, log back in typing the username and password of an administrator account. Then, launch the Windows Task Manager by holding down the control and shift keys on your keyboard and hitting "Escape." Kill the process in question by clicking it, then clicking "End Task." Log back out and back into your normal account to continue working.
Using the Command Line
You can also end a task with access denied using the Windows command line with administrator privileges.
On Windows 10 or Windows 8, right-click on the bottom left corner of the screen and click "Command Prompt (Admin)." On Windows 7, click the "Start Menu" and type "cmd" in the search box. Right-click on the "Command Prompt" icon and click "Run as Administrator."
Once you have the command line open, type "taskkill /IM "[process-name]" /T /F" and press enter, where "process-name" is the name of the process as listed in the Task Manager.
Other Operating Systems
You can run into similar issues on other operating systems, such as Linux and macOS.
In either of those operating systems, you can kill a process using the "kill" command from the command line. Open a command line window and type "kill [pid]" where "pid" is the process ID, which you can obtain using the "ps" or "top" commands.
If the kill command fails with access denied, run a "sudo kill [pid]" command. The "sudo" command will prompt you for your password and allow you to run the command as an administrator. If this doesn't kill the process, you can try running "sudo kill -9 [pid]" – which should terminate the process immediately.