How to fix error error-notification-guid-already-defined in Windows 11

Solution Steps

1. 1 First, close all instances of the application that triggered the error. Sometimes the error occurs because a previous instance didn't release the GUID. Right-click the taskbar and select Task Manager (or press Ctrl+Shift+Esc). In the Processes tab, find the application and click End Task. Then relaunch the application.
2. 2 If the error persists, restart your computer. This clears any lingering handles or GUID registrations. Save your work and restart. After reboot, try the operation again.
3. 3 If the error occurs in a specific application, check for updates. Go to the application's official website or use its built-in update feature. Developers often fix GUID conflicts in updates. For example, in Dropbox, click the icon in the system tray, select Settings, and check for updates.
4. 4 If the error is related to a driver, update your drivers. Press Windows key + X and select Device Manager. Expand the relevant category (e.g., Storage controllers, Network adapters), right-click the device, and select Update driver. Choose 'Search automatically for drivers'. This ensures your drivers are up to date and may fix GUID conflicts.
5. 5 If the error occurs during system startup, it might be due to a third-party service. Press Windows key + R, type 'msconfig', and press Enter. In the System Configuration window, go to the Services tab, check 'Hide all Microsoft services', and then disable non-Microsoft services one by one to identify the culprit. Restart after each change. This is a more advanced step, so proceed carefully.