Windows group "Backup Operators" can't SFTP

Once a user is added to the built-in Windows group "Backup Operators", SFTP will fail. Other users function normally, but users in the Backup Operators group will be unable to use SFTP. After removing the user from the group, the issue will be resolved. The same error occurs when using an SSH key.

And is this really a WinSCP problem? Or do you have the same problem with other SFTP clients?