Why am I getting Error 0x80042405-0xA001B during the stage it tries to format the USB flash drive after it finishes downloading Windows 10? This happens at around 50% when creating installation media. The only workaround is to download the ISO and use Rufus to write the ISO. This is not a fix but is only a workaround.
Since you used Rufus on the flash drive, is it GPT partitioned?
No, I only used Rufus as a workaround, also I used the alt-e cheat mode so that it uses MBR and a single FAT32 partition for dual-boot for both BIOS and UEFI which is the same partition layout used on the Microsoft official retail USB stick. I also use alt-t to preserve the time stamps of the installation files. The install.esd is less than 4GB.
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I contacted Microsoft and did a remote session and they copied the MCT to the USB flash drive and ran it from the USB drive but still got the same error. They also downloaded the ISO from MCT and ran diskpart commands to reformat the drive and copied the ISO file to the USB drive and then when I tried to boot the USB it won't boot because they only copied the single ISO file to it and the session ended.
The error code is different with the 1903 MCT, but I suspect the cause will still the same. I could create a similar failure at the same point in the process back in 2017. That would have been using the 1709 MCT.
This can happen if the usb has previously been formatted as gpt (for example, by Rufus). You can reformat it afterwards, but unless you use something like Diskpart or MiniTools Partition Wizard it is all too easy to leave it as gpt without realising.
USB flash drive --assign drive letter back to dynamic from staticBree said:...I have now confirmed that the Media Creation Tool fails with error code 0x80004005 - 0xA001A if the USB you ask it to use has a gpt partition.
After failure, the USB is left 'unalocated'. You can create a new simple volume using Disk Management to make it accessible again but, critically, its is STILL using a gpt partition layout. Only DISKPART or a tool like MiniTool Partition Wizard can make it MBR again.
The MCT only fails after it has downloaded all the files it needs, verified them and created the media in preparation for copying it to the USB. It is not until this point that it attempts (and fails) to format the USB.
Unfortunately, the MCT cleans up after itself at close, so you have to do the whole download over again next time you run it.
I did a clean and then used disk management to create an mbr fat32 partition and tried mct again but still get the same error. The only difference in the error code is that with 1903 MCT the second part is 0xa001b where in the 1809 MCT the second part is 0xa001a. The first part is 0x80242405. If the USB was GPT the first error code would be 0x80004005 but that's not my case since I don't have a GPT partition.
Microsoft DiskPart version 10.0.18362.1
Copyright (C) Microsoft Corporation.
On computer: DESKTOP-9AIOD18
DISKPART> list disk
Disk ### Status Size Free Dyn Gpt
-------- ------------- ------- ------- --- ---
Disk 0 Online 1863 GB 0 B *
Disk 1 Online 58 GB 0 B
DISKPART> select disk 1
Disk 1 is now the selected disk.
DISKPART> rescan
Please wait while DiskPart scans your configuration...
DiskPart has finished scanning your configuration.
DISKPART> clean
DiskPart succeeded in cleaning the disk.
DISKPART> create part pri
DiskPart has referenced an object which is not up-to-date.
Refresh the object by using the RESCAN command.
If the problem persists exit DiskPart, then restart DiskPart or restart the
computer.
DISKPART>
Ive had exactly the same problem mate several months ago. I thought Id completely cured it when I uninstalled McAfee and used Windows Defender instead. The issue completely went away and Ive used the Media Creation Tool with different USB flash drives a few times with no issues at all. The other week I tried creating a USB flash drive with 1809 and the problem was back...error message at 50% again! Im still using Windows Defender. No GPT partition...flash drive was cleaned, converted to MBR as a precaution and formatted FAT32. At that point I gave up on it MCT creating the media. I just downloaded the ISO, mounted it and copied the files onto the flash drive
Should my windows drive be MBR also? I did the command and found both the USB drive I created, as well as the main OS drive had ended up as GPT. Somehow, that doesn't seem correct to myself. Can someone confirm this?
It is an HP Envy M6-1178sa machine with UEFI if that makes any difference
Last edited by Spitfire400; 29 May 2019 at 13:20. Reason: Additional Info
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