If we encounter this error 0x80070057 while backing up our system, it is usually due to a problem with the formatting of the decimal point, which may occur if the language and region are set to something other than English (United States).

The official documentation for this problem statement is linked below:

/kb/982736/en-us

Please turn on Region and Language in the Control Panel.

On the Format tab, click on "Other Settings" and change the decimal point to "." (no quotes).

Click OK and restart your computer to make sure the problem is solved.

We can also try to fix the problem by modifying the registry keys.

Type regedit into the search box on the Start menu and click Enter to open the Registry Editor.

Locate the following key:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\System

Create a new DWORD value in the right window.

Rename it to CopyFileBufferedSynchronousIo.

Change the value to 1 and close the registry editor to see if the problem can be solved

Rename it to CopyFileBufferedSynchronousIo.

Close the registry editor to see if the problem can be solved.