Windows 10: USB flash drive --assign drive letter back to dynamic from static

Hi Bree, I just wanted to let you know that I followed the instructions exactly and changed from GPT back to MBR. I ran the Media Creation Tool again to create a bootable USB flash drive. I got that exact screen popping up again at 50% whilst creating the media. This time the error message was slightly different Error 0x80042405-0xA001A. It looks like I'm going to have to give up on the Media Creation Tool and use Rufus instead to create the bootable USB after downloading the ISO again with the Media Creation Tool

 

Hi,

Why not use MCT to create an ISO file. You can then use it as many times as you like to create installation media without having to download anything.

Further to the error code :

https://answers.microsoft.com/en-us/...ea5b7d1?auth=1

and:

https://answers.microsoft.com/en-us/...7-ca9c4f17e74f

Cheers, *Wink

 

Just for my peace of mind. This is a fresh copy of the MCT tool, correct?

One hit suggested using Disk Cleanup and cleaning up all old system files.

I searched your error code and other have this error, recently. Had to laugh. On the MS forum a community moderator suggested using Rufus instead of getting down to root cause with MS's tool.


Ken

 

Yeah that's what I'm going to do mate. Having just wasted a couple of days messing about trying to get to the bottom of the problem. I plan to use Media Creation Tool to just download the ISO. Then download Rufus to create the bootable USB from the downloaded ISO. That's what you mean isn't it?
Do you think I need to remove any remains of the Media Creation Tool attempts from my hard disc? I wouldn't have a clue where to look though.
Also, should I doing anything with my USB flash drive to prepare it before using Rufus ...reformat it or something more? Or will Rufus sort it out?
As to your two links you've posted on the error code. I googled the error code and theres loads of people having the same issues.

 

Hi Ken. Yeah its a newly downloaded Media Creation Tool this morning. The USB flash drive is 16gb so size isn't the issue either. Do you think I need to do anything with files on my PC or prepare the USB flash drive in any way before using Rufus? I'm going to use the Media Creation Tool to download the ISO and then use Rufus to create the bootable USB flash drive using the downloaded ISO.

Yeah, Ive seen loads of people having the same problem. I saw that moderators post too suggesting Rufus. It definitely appears to be Microsoft who need to get the Media Creation Tool sorted out. It looks like its been going on for a while

 

Apparently you are not alone, at least 110 other have this problem...
https://answers.microsoft.com/en-us/...8-ce7d2ea5b7d1


There's no need for Rufus though. Just make an ISO using the MCT, mount it, then copy everything from it to a USB prepared using the following DiskPart commands:

SELECT DISK n
(use the appropriate disk number in place of 'n')
CLEAN
CREATE PARTITION PRIMARY
SELECT PARTITION 1
FORMAT FS=FAT32 QUICK
ACTIVE
(only required for legacy boot, UEFI doesn't need this)
EXIT

 

I would run the disk clean up tool although it shouldn't be necessary. The ISO is self contained.

Here is another alternative to Rufus using Diskpart. I used it successfully to create a bootable Kyhi's recovery disk.

Image Restore from Network Location?? - Windows 10 Forums

Yes I saw that comment of USB size and remembered you said yours was 16GB.

Post back progress. Can't believe MS is putting resources to solve.

Good luck

 

Hi,

Yes, you could do that. If your machine is fully UEFI comatible and uses that there's even no need to use Rufus. Just mount the ISO created by MCT, select all files and copy these to your flash drive.

Windows writes these to "Windows\SoftwareDistribution\Downloads"

If it's already formatted using the FAT32 file system then the only thing to do is to delete any files on it.
When using Rufus select your W10 ISO file as a source and select the correct settings for BIOS/UEFI or both if you like.

Cheers, *Wink

 

Hi Bree. I printed off some instructions from Dell last year. Are these the same?
LIST VOLUME
SELECT VOLUME n (use appropriate volume number)
CLEAN
CREATE PARTITION PRIMARY
FORMAT FS=FAT32 LABEL='OS INSTALL' QUICK
ACTIVE
EXIT

I don't understand the difference between Select Disk and Select Volume as Dell suggested?
I also see that after Create Partition Primary...you type Select Partition 1.
Also..I do have UEFI but is it OK to leave the ACTIVE command typed in..would it cause a problem?
Do you mind explaining the 2 differences above a bit so I have some understanding? I like to learn along the way if that's OK with you mate

 

Both ways work and make an mbr-type USB (I've just tested that).

I use SELECT DISK to be sure that I've cleaned the partitioning type of the usb first, then diskpart will use mbr by default when you make the new partition.

Not at all - UEFI ignores it. It just makes the usb bootable on legacy systems as well as UEFI.

 

If I use Rufus I know it wants to set up the GPT partitioning for my UEFI system as a default..so would you use that instead of MBR?
I'm confused now ..I don't know whether to use Rufus or the Mount method that Bree has mentioned and you have mentioned too. I did a quick search of Tenforums to see if there was a tutorial I could print off but I couldn't find one with the Diskpart commands etc

 

Hi,

Since you're running UEFI there's no need to use a third party programme. Double clicking the ISO file mounts it and assigns a drive letter. All you need to do is select all files there and copy them to you USB stick.
It should boot off of it when you call the boot menu selection (F12 or something like that) or set boot order in UEFI to USB first.

The advantage of leaving the stick as MBR and set as Active is that it can be used for both UEFI and BIOS machines whereas GPT is only for UEFI machines.

O, since you're confused about the difference between a "Volume" and a "Disk"
A volume is a or several partition(s) on a disk or spanned across disks for instance whereas a disk is a physical unit like a hard dirve, usb stick. Whether or not these contain several volumes or not is irrelavant to the disk command in diskpart.




Cheers, *Wink

 

Look at it this way - the MCT makes a 'universal' usb that will boot and install as UEFI (if that's the type of machine you boot it on) or a legacy mbr install for older machines. The diskpart commands and the files from the ISO makes a usb that's identical to the one the MCT would make (or the one you'd buy in a Windows 10 box from Microsoft).

 

Have you come across a tutorial on here with the Diskpart Commands that are to be used to prepare the USB flash drive before mounting the ISO and copying the files across? Id print a copy if I could find one.
From your explanation above..If I'm understanding you correctly...Select Disk instead of Select Volume is better if you are going to clean and format the flash drive because when you select Clean after Select Disk..if there were several volumes on that disk it would automatically clean all the volumes as well. Have I got that right?
Ive just been discussing the Diskpart commands above with Bree. Diskpart is something I don't really understand

 

Hi,

Can't say I recall ever seeing one but it's all really straightforward once you get your head around it.

The "clean" command wipes the entire phycial disk regardless of the amount of volumes it contains. I don't think it will even run when no disk is selected anyhow. (Need to check that) It's a very powerful command so you're not allowed to makes mistakes or you'd lose the content of a disk when the wrong one was chosen.

Most common flash only have a single partition (so one single volume) on them in factory state.

Cheers, *Wink