Lỗi someone else is still using this pc

Did you run into a “someone else is still using this PC” pop-up window while restarting or shutting down your Windows computer? Was there a secondary message that any unsaved data will be lost for other users on the device? Don’t let these pop-ups alarm you.

The warning pointing to simultaneous logins doesn’t necessarily mean that someone else has logged in to your PC. Mostly, the error results from invalid user login instances, but sometimes it shows up out of the blue with no traceable cause. It is easy to resolve, though, and does not require any advanced troubleshooting techniques. The following Microsoft-recommended fixes for Windows 11 and Windows 10 can get rid of the error message.

Also read: How to Add Portable Apps to Windows Startup

1. Remove Other Local Accounts on Your PC

It’s common to have more than one user account on a device without the main PC user – you – knowing that it exists. These secondary local accounts may have been set up during Windows installation or for a specific purpose, such as setting up a kiosk mode. Therefore, you should first look at removing these unnecessary accounts.

1. Start the Run dialog using Windows + R and type “netplwiz,” which stands for Network Places Wizard. This command is concerned with managing multiple user accounts enabled on your system.

1. Check whether there are any secondary users in the “Users for this computer” space. They may be assigned to the “Administrators” group.
2. Remove the extra user accounts. It is easy to identify them since the option to remove your main administrator account will be disabled.

1. Press Windows + L to check the lock screen status on your device. The secondary local user accounts should not be visible after removing them from the netplwiz User Accounts window.

1. Alternatively, you can check “Family options” for your Windows device from System settings.

1. If there are multiple user accounts under “Family & other users,” consider removing the ones that aren’t listed as “Organizer.”

Also read: How to Use Google Authenticator on a Windows PC

2. Enable Secure Sign-In

For additional security, Windows provides a secure sign-in option that requires users to press Ctrl + Alt + Delete on their lock screen for desktop access. While it may feel tedious to use this shortcut in the beginning, know that it’s the most secure way to sign in to your device – your device is safe from any malicious programs that attempt to replicate a fake login.

1. Open the Run dialog [Windows + R] and type “netplwiz” to open the User Accounts panel.
2. Go to the “Advanced” tab and check the box for “Secure sign-in.” In the future, all login attempts will have to go through a Ctrl + Alt + Delete procedure.

1. To unlock your PC, instead of Ctrl + Alt + Delete, you can also press and hold the power button, then press the volume down button.

Also read: How to Change Account and User Name on Windows

3. Check Failed Login Attempts Using Event Viewer

Windows has a superb Event Viewer application that keeps track of each and every activity on your PC, and that includes any background processes. Using its audit capabilities, it is very easy to keep track of all successful and failed login attempts. If you’re not sure which login was invalidated during sign-in, you’ll find out here. This makes it easy to take any corrective actions.

1. From the search bar, search for the “Event Viewer” application and run it as administrator.

1. The Event Viewer gives a quick glance at all errors on your window pane. As long as the error isn’t labeled “critical,” there’s nothing to worry about. Check the error pane for any errors due to user login.

1. If no helpful login instances are visible on the main window, navigate to “Windows Logs -> Security” from the sidebar to view recent security-related events on your device.
2. Focus on the “Logon” task category. It will have an event ID like 4624, which concerns every successful and failed attempt to log in to Windows.

1. If the logon event displays an “audit failure” in the details pane, this is your first clue about user authentication problems on your device.

1. Go to the “Details” tab of the failed login and find the failed login attempt. It is most certainly tied to a local user account that you can see under “TargetUserName.”

1. Consider removing the error-prone local user account from your PC.
2. If the failed login is due to some other reason, such as a third-party antivirus or some unfinished update or process, you can take corrective steps as discussed in the next few solutions.

Also read: How to View and Clear Activity History on a Windows PC

4. Check Task Manager for Incomplete Tasks

Often, unfinished tasks in Windows can lead to the “someone else is still using this PC” error. These tasks are usually queued printing tasks and need to be resolved right away. If there are still a few traces of other users’ activities on your PC, these also need to be removed from the queue. The Task Manager in Windows is the best place to approach these error sources.

1. Open Task Manager using Ctrl + Alt + Delete and head to the “Users” tab.
2. check whether there are other users’ activities showing on your device and right-click to end those tasks for that user. If only the Admin user is showing, nothing is required.
3. Go to the “Processes” tab to view any unfinished printing tasks. End them with a right-click, then shut down and restart your device.

5. Install Pending Updates

If you haven’t updated your Windows PC in a while, the unfinished updates may cause user sign-in problems, as all Windows updates are tied in with the system user credentials. The best way to resolve these errors is to manage and finish your Windows updates.

1. Search for “Check for Updates” in the Windows search bar and look for any unfinished updates.
2. Finish downloading the updates and restart your PC.
3. Moving forward, you should not experience problems due to your local user accounts accumulating unfinished updates.

Also read: 6 Ways to Stop Windows Updates

6. Remove and Reinstall Third-Party Antivirus Software

Windows Defender is the default antivirus in all Windows 11 and Windows 10 devices. While you can use third-party antiviruses in addition to Windows Defender, it may be unnecessary and sometimes not worth the trouble. The challenge is that when a third-party antivirus is active, Windows Defender’s Real-time protection is turned off by default. You cannot reenable it without uninstalling the antivirus first.

If you notice user account problems on your Windows PC, it is a good idea to temporarily uninstall the antivirus from “Add or Remove Programs.” You can reinstall it later if you find it necessary for your computing tasks.

Also read: What Happens If You Don’t Activate Windows?

7. Run System Restore to Fix User Account Problems

If you’re not sure what is causing the user authentication problems on your device, and if the Event Viewer audit [see above] is too vague on the details, you may consider running System Restore to fix the user account issues.

1. Open System Restore from the Windows search bar.
2. Go to the “System Protection” tab and click the “System Restore” button.
3. Select the “Recommended restore” option, which will take your PC back to an earlier snapshot that is saved by default. [Alternatively, you can choose a different restore point.]
4. Follow the on-screen instructions and authorize the restore process. The system will automatically restart, and any recent bugs will be removed.

Also read: 9 Simple Ways to Open Device Manager in Windows

8. Reset Your Sign-In Requirements

On a Windows device, you can use a variety of sign-in options, such as a text-based password, PIN [Windows Hello], physical security key or a picture password. When facing user authentication problems, it’s advisable to reset your credentials on the device and restart.

1. Go to “Accounts -> Sign-in options” and change the sign-in procedure for your device.
2. If you use a password, click “Change.”

1. You’ll be guided through a set of instructions to modify the password for the main admin user.
2. Restart your device with the new password. Once your authentication is successful, any future issues due to multiple sign-ins should resolve themselves.

Note: It’s much easier to use Windows Hello, a 4-digit PIN that requires a one-time setup, intead of a password.

Also read: What Is Windows Hello and Should You Use It?

Frequently Asked Questions

Can you tell whether someone else is using your Windows computer?

Yes. There are several ways to tell whether someone else is using your PC while you have been away or remotely. One way is via the Windows Event Viewer’s “Security” menu, which makes it easy to get a quick glimpse of all accesses and logins on your device. Any remote login attempts can be determined by doing a quick audit on Event Viewer.

Is it safe to use local accounts in Windows?

Using local accounts in Windows is completely safe as long as they’re on your own devices. As an administrator, you will only get sign-in error messages when you forget to log off from signed-in Microsoft, Gmail or Skype accounts during a restart. In fact, using a local account is better in some ways. Many Windows users employ the Administrator account for daily use, which makes a PC more vulnerable if it is hacked.

Can I manage another user's login in Windows?

As long as you are the “other user” with access to the email account used to log in to Windows, it is easy to manage your own third-party accounts. However, if you added a third user through the “Family & Other Users” option, you will not be able to manage those sign-ins without knowing the password, one-time password [OTP] and other credentials for that account.

Image credit: Adobe Stock All screenshots by Sayak Boral

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Sayak Boral is a technology writer with over eleven years of experience working in different industries including semiconductors, IoT, enterprise IT, telecommunications OSS/BSS, and network security. He has been writing for MakeTechEasier on a wide range of technical topics including Windows, Android, Internet, Hardware Guides, Browsers, Software Tools, and Product Reviews.