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.

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.

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.

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.

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.

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.

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.

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.

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. Note: It’s much easier to use Windows Hello, a 4-digit PIN that requires a one-time setup, intead of a password. Image credit: Adobe Stock All screenshots by Sayak Boral