If you are creating a bootable USB drive with the Windows media creation tool and it creates an error called 0x80004005 – 0xa001a then the answer is rather simple and easy to solve. If you had downloaded the Windows 10 ISO and use the Windows 7 USB/DVD download tool to create the media the the error is created by your anti-virus.
The antivirus software normally blocks the creation or running of a bootable file and this creates the problem where you cannot create a bootable USB drive for Windows. Note that you can disable the “Real Time Protection” while you start the process and complete it. You can then remove the bootable USB drive and then enable the “Real Time Protection” on your anti virus again. The solution is rather simple.