There is a file called NTUSER.DAT hidden in each user profile. This file contains each user's settings and preferences, so you shouldn't delete it, and you probably shouldn't edit it. Windows will automatically load, change, and save the file for you.
NTUSER. DAT contains your user profile settings
Every time you change the appearance and behavior of Windows and installed programs, whether it's your desktop background, monitor resolution, or default printer, Windows needs to remember your preferences the next time it loads.
Windows does this by first storing that information in a HKEY_CURRENT_USER in the registry, and then when you log off or shut down, Windows saves that information to a NTUSER.DAT file.
The next time you log in, Windows will load NTUSER.DAT into memory, and then your settings and preferences will be loaded into the registry again. This process allows you to make personal settings that are unique to your user profile, such as the desktop background of your choice.
名称NTUSER.DAT是Windows NT的剩余物,最初是在Windows 3.1中引入的。 Microsoft将DAT扩展名用于任何包含数据的文件。
Each user has a NTUSER.DAT file
User profiles are not always fully supported by Windows. In earlier versions, when you started Windows, every user of the computer saw the same desktop, files, and programs. Windows now better supports multiple users on the same machine, and it does this by placing NTUSER.DAT files in each user profile.
You can either open File Explorer and browse to "C:\Users\Your username", or type "%userprofile%" in the file resource manager's address bar and press Enter.
If you don't see the NTUSER.DAT, don't worry, Microsoft don't want you to edit or delete the file, so they'll hide it. You can enable the "Show hidden files" option to make the files visible. Click "View" and tick the box next to "Show hidden items".
You may notice that in addition to NTUSER.DAT file, there is one or more ntuser.dat.LOG files. Every time you make a change, Windows saves your preferences to NTUSER.DAT file. But first, it makes a copy and renames it to ntuser.dat.LOG (plus an incrementing number) to back up your previous settings. Even Microsoft knows that you should always back up your settings and files.
Don't delete NTUSER.DAT files
You should never delete your NTUSER.DAT files. Because Windows relies on it to load your settings and preferences, removing it will corrupt your user profile. The next time you sign in, you'll see a prompt that Windows can't sign in to your account.
Although some people suggested that logging out and then logging back in might solve the problem, you'll see the same message again. If you try to create a normal NTUSER.DAT file to replace the missing instance, you'll run into a loop in the first setup dialog and Windows will never be able to complete the login.
NTUSER. A DAT file is usually not a large file, with 3 megabytes on one of our new computers and 17 megabytes on our computers that we have used for a few years. Deleting it usually doesn't regain much space, but the results can be catastrophic. If you don't need a user profile, it's best to delete the user account through Windows.
You probably shouldn't edit it either, and some admins may do it to make quick changes to many users, but it can lead to problems that are difficult to resolve if you're not careful.
Better yet, make changes through the registry. Modifying the registry is also something you should be cautious about, but there's a good chance you'll find a guide that guides you through the necessary steps. After you edit the registry, the next time you log out or close, your new settings will be saved to NTUSER.DAT file.