What causes 0x80042405-0xa001a error at 50% during creating Windows 10 Media on USB flash drive when running the Media Creation Tool? I have Windows 10 April 2018 Update and need to update the installation media.
That is the point at which the MCT tries to format the USB. The error is due to the USB having a GPTpartition table, something the MCT cannot cope with as it expects an MBR partition table. Usually the USB got reformatted to a GPT layout by previously using Rufus.
Rather than making a USB, use the MCT to make an ISO. this can easily be put onto a USB later. Use Rufus (if you insist), but the easiest way is to just mount the ISO, copy the files to the USB and mark its partition Active.
USB flash drive --assign drive letter back to dynamic from static Solved - Page 3 - Windows 10 ForumsBree 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. This is usually due to having use Rufus to format the USB previously.
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.
This seems to be a common error for some, MCT can be fickle when creating and writing to thumb drives. Sure you have, but ensure you are getting the correct version. Language, home/pro, and the bits.. 32-bit or 64-bit. If that fails again, choose the option to just create the ISO only, you can choose where to let Windows create it. Then use another common Thumb Creator to actually make the thumb drive, Rufus. It will handle all the formatting and creation for you.
Rufus - Create bootable USB drives the easy way
but it was Rufus that caused the USB to be 'unuseable' by the MCT in the first place by making it GPT!
Diskpart can make a suitable USB. Then just mount the ISO and copy all the files to the USB.
SELECT DISK #Code:Microsoft DiskPart version 10.0.17134.1 Copyright (C) Microsoft Corporation. On computer: DELL-E7440-W10 DISKPART> LIST DISK Disk ### Status Size Free Dyn Gpt -------- ------------- ------- ------- --- --- Disk 0 Online 465 GB 1024 KB * Disk 1 Online 7634 MB 7632 MB * DISKPART> SEL DISK 1 Disk 1 is now the selected disk. DISKPART> CLEAN DiskPart succeeded in cleaning the disk. DISKPART> CREATE PARTITION PRIMARY DiskPart succeeded in creating the specified partition. DISKPART> SELECT PARTITION 1 Partition 1 is now the selected partition. DISKPART> FORMAT FS=FAT32 QUICK 100 percent completed DiskPart successfully formatted the volume. DISKPART> ACTIVE DiskPart marked the current partition as active. DISKPART> LIST DISK Disk ### Status Size Free Dyn Gpt -------- ------------- ------- ------- --- --- Disk 0 Online 465 GB 1024 KB * * Disk 1 Online 7634 MB 0 B DISKPART>
Where does it say that in the OP's post?
Diskpart can make a suitable USB. Then just mount the ISO and copy all the files to the USB.
SELECT DISK #Code:Microsoft DiskPart version 10.0.17134.1 Copyright (C) Microsoft Corporation. On computer: DELL-E7440-W10 DISKPART> LIST DISK Disk ### Status Size Free Dyn Gpt -------- ------------- ------- ------- --- --- Disk 0 Online 465 GB 1024 KB * Disk 1 Online 7634 MB 7632 MB * DISKPART> SEL DISK 1 Disk 1 is now the selected disk. DISKPART> CLEAN DiskPart succeeded in cleaning the disk. DISKPART> CREATE PARTITION PRIMARY DiskPart succeeded in creating the specified partition. DISKPART> SELECT PARTITION 1 Partition 1 is now the selected partition. DISKPART> FORMAT FS=FAT32 QUICK 100 percent completed DiskPart successfully formatted the volume. DISKPART> ACTIVE DiskPart marked the current partition as active. DISKPART> LIST DISK Disk ### Status Size Free Dyn Gpt -------- ------------- ------- ------- --- --- Disk 0 Online 465 GB 1024 KB * * Disk 1 Online 7634 MB 0 B DISKPART>
No, this OP hasn't said they used Rufus (yet) but in all previous cases Rufus was to blame, as the OP admitted here...
USB flash drive --assign drive letter back to dynamic from static Solved - Page 3 - Windows 10 Forumsit may have been the USB flash drive that I once used with Rufus. That would have set up GPT on it.
Ok, somebody had a boo-boo with Rufus sometime. Doesn't make it worthless or destructive. It really is used by a lot of people successfully and often. All the Diskpart stuff works, too. Bit more complicated for the average user, but works. Rufus is not a vile piece of software.
Well, in that case....suggest the OP simply reformat the thumb FAT32 and start over with MCT. That's pretty simple. No pitfalls there except MCT itself.
Unfortunately the USB has to be cleaned by diskpart - there's no other way to revert from the gpt layout to the mbr layout with any other built-in MS tool. File Explorer or Disk Management cannot change the partition table type - just delete/create/format partitions using the gpt table that already exists.
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