It is well-known that Windows is a pretty unstable operating system, and you never know what error message you would be greeted with when you start your PC in the morning, after working normally and shutting it down properly the previous night. For instance, sometimes even the Task Manager fails to open. Even though the issue sounds quite small in nature, and in many cases a simple restart fixes the problem, if you have trouble opening the app even after several reboots, the following sections help you get a permanent solution. An Overview There are times when you need to check how many tasks are running in the foreground and background. Or, in some cases an app that you are working on stops responding all of a sudden, and you are required to end its task. In any such situation, you must open the Task Manager, from where all the active instances of the programs and services can be seen and managed. However, sometimes you may notice that when you try to open the Task Manager, it fails to launch. Some of the common reasons behind this weird behavior are listed below Corrupt System Files While using a Windows computer, if you have a habit of turning off the PC abruptly, without shutting down the operating system properly, the system files may get corrupted over time. If, by any chance, any such erroneous file is directly or indirectly related to the Task Manager, the app won’t open. Corrupt User Profile Every time you create a new Windows user account and sign in to it for the first time, a new user profile for that account is created. This profile contains all the user-specific settings and privileges, and launches a separate instance of every built-in or third-party app when initialized. If the user profile gets corrupted, the chances are that you won’t be able to use the Task Manager as the app wouldn’t open. Absence of the Relevant Registry Entry Because even the Task Manager in Windows has its own registry entry, if any information related to the app isn’t available in Windows Registry, the Task Manager would fail to initialize. Depending on the cause of the issue, there could be some relevant solutions. However, because it is quite challenging to understand the reason of the problem, you may need to try each suggestion one-by-one until the trouble is fixed. Some of the easiest and most straightforward remedies that you can try to make the Task Manager work again include Solution 1 Run System File Checker For Corrupt System Files System File Checker is a built-in utility in the Windows operating systems that scans and fixes any issues that the system files may have. If the files are irreparable, the System File Checker tool replaces them with the new one. To use System File Checker, you must launch it from an elevated Command Prompt window which is the instance of the command-line interface that has all the administrator privileges. You can learn how to open an elevated Command Prompt window and use the System File Checker utility by following the instructions given below Step 1 Launch Elevated Command Prompt Window Type CMD in the Cortana search box present in the Taskbar, click Run as administrator from the right pane of the results list, and click Yes on the User Account Control confirmation box to open an elevated Command Prompt window. Alternatively, you can also right-click Command Prompt from the results list, and click Run as administrator from the context menu. Step 2 Run System File Checker In the command-line interface, type SFC /SCANNOW and press Enter. Wait while the utility scans, detects, and fixes any issues with the system files. Step 3 Restart Windows Type EXIT in the command-line interface and press Enter to close the Command Prompt window. Now, restart Windows normally and let the changes take effect. Upon successful reboot, try opening the Task Manager again. Solution 2 Create a New User Account For Corrupt User Profile In case the user profile is corrupted, you can try creating a new user account, sign in to that account to allow Windows to generate a new user profile, and then try opening the Task Manager from there. You can either create a Microsoft account that requires some personal details like a different email ID and/or a phone number, or you can try creating a local account if you only want to see if the user profile is faulty. For this illustration, a local account is created for simplicity. You can learn how to create a new local user account in Windows 10 by following the instructions given below Step 1 Get to the Accounts Window Go to Start > Settings, and click the Accounts tile from the Windows Settings box. On the next screen, click Family & other users from the navigation pane at the left. Step 2 Create a New Local Account Click Add someone else to this PC from under the Other users section. On the Microsoft account box, click I don’t have this person’s sign-in information. On the next screen, click Add a user without a Microsoft account. On the Create a user for this PC screen, populate the fields with the relevant information, and click Next to create a new local user account. Step 3 Sign in to the New Account Click Start and then hover the mouse over the User icon. Next, click the name of the new user you created in the previous step to sign in to that account without signing out from the current one. Try opening the Task Manager from the new account. Solution 3 Add a New Windows Registry Entry For Absence of the Relevant Registry Entry Because Windows Registry plays a vital role in the functioning of the operating system, if the appropriate Task Manager entry is missing from the Registry or its value is set incorrectly, the app won’t open. To fix this, you must create a new entry or replace the wrong value with the correct one. For this illustration, it is assumed that the entry is missing altogether. To learn how to add a new Windows Registry entry for the Task Manager, you can follow the instructions given below WARNING and DISCLAIMER Modifying Windows Registry incorrectly may make your computer behave unexpectedly or become permanently unstable. The owner of the website, the author of this post, or any other person directly or indirectly related to Wondershare will NOT be responsible for any data loss or damages caused to your PC if Windows Registry is not handled properly by you. Step 1 Get to Windows Registry In the Cortana search box, type REGEDIT and click Registry Editor from the results list. Click Yes on the User Account Control confirmation box to open the Registry Editor console. Step 2 Add a New System Key Note You can skip this step if the System key is already present in the Registry. From the navigation bar at the left of the console, go to HKEY_CURRENT_USER\Software\Microsoft\Windows\Current Version\Policies Next, right-click Policies, go to New, and click Key. Rename the new key as System to create a new System key. Step 3 Add a DisableTaskMgr DWORD Value Note You can skip this step if the DisableTaskMgr DWORD is already present in the Registry. Right-click the System key that you created in the previous step, go to New, and click DWORD 32-bit Value. Rename the new DWORD as DisableTaskMgr. Step 4 Configure the Value of DWORD and Restart Windows Double-click the DisableTaskMgr DWORD from the right window of the System key, and change the current Value data to 0 if it is not already configured. Click OK to save the changes, close Windows Registry, and restart the computer to ensure that the changes become effective. Tips to Avoid the Issue Some tips that can help you avoid this problem from arising in the first place are listed below Make sure to update Windows and all the device drivers regularly Always use the proper method to shut down the computer Always install the applications obtained from the reliable and trusted sources Always scan a newly connected flash drive or any other storage media for viruses before opening it in File Explorer The Bottom Line There could be many reasons for the Task Manager not opening. Some of the most common ones include faulty system files, corrupt user profile, absent or incorrectly configured Windows Registry entry, etc. While the issue can be fixed simply and quickly using some basic tweaks, it would be wise to take precautionary measures like scanning for viruses, installing apps from the trusted vendors, etc. to prevent the issue from coming up. It is also imperative to mention here that configuring Windows Registry incorrectly may make your computer permanently unstable. Therefore, you are strongly suggested to use that solution only and only if you are comfortable with and have some prior experience in handling the Registry. People Also Ask Q1 What if Windows Registry already has the DisableTaskMgr or System entries present in it? A1 If the System key is already present, you can create a new DisableTaskMgr DWORD value and change its value data to 0. If the DisableTaskMgr DWORD value is preset as well, merely changing its value data to 0 should suffice. Q2 Can I create a new Microsoft account with the same email ID and phone number instead of a local account if my user profile is corrupted? A2 Yes, you can. To do so, you must first convert your currently active account to a local account. This would make your Microsoft account independent. After this, you can create a new Microsoft user account using the same ID. All this can be done by going to Start > Settings > Accounts. Q3 What if I leave the issue alone and don’t care to rectify it? A3 You can do so. However, if you ever want to end a running task forcefully, you wouldn’t be able to open the Task Manager.