Due the restriction or policies with in the computer or user when you try to open Task Manager, you may receive the following error “Task Manager has been disabled by your administrator”. This can be resolve in several ways.
Method 1
Click Start, Run and type this command exactly as given below:
REG add HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System /v DisableTaskMgr /t REG_DWORD /d 0 /f
Method 2
1. Click Start, Run and type Regedit.exe
2. Navigate to the following branch:
HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Policies\ System
3. In the right-pane, delete the value named DisableTaskMgr
4. Close Regedit.exe
Method 3: Using Group Policy Editor
1. Click Start, Run, and type gpedit.msc and click OK.
2. Navigate to this branch:
User Configuration / Administrative Templates / System / Ctrl+Alt+Delete Options / Remove Task Manager
3. Double-click the Remove Task Manager option.
4. Set the policy to Not Configured.