If you have an old user account on your Mac that you can no longer access, there's a way you can still get into it as long as you have an "Administrator" account on that Mac. Just get into the System Preferences from the Apple Menu and click "Users & Groups". Then click the lock icon and enter the admin name and password. Select a user, and then click "Reset Password".
Max wants to know if there's a way to reset an account on macOS without destroying the data. Leo says he can delete an account without erasing the data and then recreate it. That should clean everything out. He'll have to be an administrator, and he'll have to make sure he doesn't check the box to delete the data.
He can also reset the password to recover the account.
If you're having issues with your computer running slow, or you're getting frequent errors, it could be an issue isolated to your user account. This is especially true if you're noticing that it's taking a long time to simply log in. Creating a new, fresh user could resolve those problems and improve performance. Windows 10, however, makes it more difficult to do this with its new Control Panel. Here's what you'll need to do to create a new user on Windows 10:
Rick has had issues with all his data, favorites, and icons all disappearing. What's happening? Leo says that Windows Home Folder keeps all the stuff in it and it could be that the home directory for his log in became corrupt. It ends up logging him on with a temporary profile. Leo says that's a sure fire indication that his profile is somehow damaged. It could either be a hard drive error or a Windows error. The good news is that the data is probably still there, but he just can't see it in his account. It's likely an indication that his hard drive is starting to go South.
Jim is using Windows 8.1 and he's being asked to sign in with his Microsoft account. Leo says that both Windows and Apple are now doing that and he finds it annoying. He can set it up without it, but they'll bug him with it. Windows 10, however, will require it. How does that affect running as a standard user? Will he have to have multiple Microsoft accounts? Leo says he doesn't really know. But that's a good issue to bring up.