You can see the error below when attempting to delete your stored logon details.

To resolve this:

1. Close your Sage 50 Accounts program.
2. Right-click your desktop shortcut for Sage 50 Accounts, and then click Run as Administrator.
3. Attempt to delete your stored credentials again. 

TIP: To delete your stored credentials, click Settings, then User Management and then click Delete stored logon details.