The most recurrent reason behind the issue is that Windows 10 version installed on your system is not compatible with QuickBooks Desktop. This means that QuickBooks runs for different Windows versions other than Windows 10 O/S. As a precedent, QuickBooks is configured for Windows XP or any other operating system, and you're using Windows 10. However, once it fails to do so, the backups stop working. Read this blog till very end and fix the QuickBooks backup not working windows 10 error.