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

Page 3 of 8 FirstFirst 12345 ... LastLast
  1. Bree's Avatar
    Posts : 8,808
    10 Home x64 (1809) (10 Pro on 2nd pc)
       17 Dec 2017 #21

    sportsfan148 said: View Post
    How would I resolve it with my flash drive if that's the case?
    Use DISKPART, be very careful to select the right USB drive, then use its CLEAN command. That removes all partition information (you did double-check you had the USB selected? :)).

    I'm not saying gpt was the cause for you, just that it's one possible cause that's been seen before.
      My ComputersSystem Spec

  2. Caledon Ken's Avatar
    Posts : 10,577
    Windows 10 Pro x64 Build 1803
       17 Dec 2017 #22

    Would you also have to add the command convert mbr after the clean command?
      My ComputerSystem Spec

  3.    17 Dec 2017 #23

    Bree said: View Post
    Use DISKPART, be very careful to select the right USB drive, then use its CLEAN command. That removes all partition information (you did double-check you had the USB selected? :)).

    I'm not saying gpt was the cause for you, just that it's one possible cause that's been seen before.
    Yes Id done everything correctly. Its a method Ive followed several times before without issue. I might be better off just using Rufus. I'm not familiar with Diskpart at all
      My ComputerSystem Spec

  4. Bree's Avatar
    Posts : 8,808
    10 Home x64 (1809) (10 Pro on 2nd pc)
       17 Dec 2017 #24

    Caledon Ken said: View Post
    Would you also have to add the command convert mbr after the clean command?
    No. There's no partition info at all after CLEAN - nothing there to convert. You could use CREATE PARTITION PRIMARY after CLEAN, that makes a MPR partition. Then format it with DISKPART, Disk Management or whatever you like.
      My ComputersSystem Spec

  5. Bree's Avatar
    Posts : 8,808
    10 Home x64 (1809) (10 Pro on 2nd pc)
       17 Dec 2017 #25

    sportsfan148 said: View Post
    I might be better off just using Rufus. I'm not familiar with Diskpart at all
    I've looked at Rufus and come to the conclusion it has too many options - it's all too easy to leave some obscure option selected that makes a USB that won't boot. There are so many threads complaining of that.

    An alternative to using the MCT to make a bootable USB is to use it to make an ISO file. You can then just double-click on the ISO to mount it then copy the files to a USB, prepared using DISKPART. Here's how....

    Create Bootable USB Flash Drive to Install Windows 10 (post #270)
      My ComputersSystem Spec

  6.    17 Dec 2017 #26

    I wonder if it was the GPT partitioning problem you mentioned that caused my errors. All I did was format the drive in Windows to remove the previous Windows 10 Anniversary update which was on the drive and had been successfully created with the Media Creation Tool. When youre creating your bootable drives do you format the drive manually as an extra step before you use the Media Creation Tool. I know Media creation Tool formats the drive during the Media Creation process anyway but Ive always quick formatted it in Windows to blank the USB before starting the process
      My ComputerSystem Spec

  7. Bree's Avatar
    Posts : 8,808
    10 Home x64 (1809) (10 Pro on 2nd pc)
       17 Dec 2017 #27

    sportsfan148 said: View Post
    When youre creating your bootable drives do you format the drive manually as an extra step before you use the Media Creation Tool...
    No. The MCT should format for Fat32 and mark the partition as active. I'm guessing though that it's only designed to expect an mbr layout and fails at that point if it finds gpt. None of my USBs have ever been gpt, so I've not tested that (yet).
      My ComputersSystem Spec

  8.    17 Dec 2017 #28

    [QUOTE=Bree;1239221]No. The MCT should format for Fat32 and mark the partition as active. I'm guessing though that it's only designed to expect an mbr layout and fails at that point if it finds gpt. None of my USBs have ever been gpt, so I've not tested that (yet).[/Q

    I know Rufus uses GPT and recommends it for UEFI
      My ComputerSystem Spec

  9.    17 Dec 2017 #29

    Ive just checked the USB flash drive that gave me problems with the Media Creation Tool. Ive just checked it with the Diskpart instruction and the flash drive is GPT. Do flash drives normally have MBR then? I'm guessing that it may have been the USB flash drive that I once used with Rufus. That would have set up GPT on it. Can you give me a step by step if I need to convert back to MBR...if that's what required. If I can sort the problem out I'll go back to using the Media Creation Tool to create the bootable USB media. Ive searched the net and it says it can be done in Disk management. Ive just checked by right clicking on the unallocated space on the drive. Theres no convert to MBR option on the context menu. There is a tutorial on here that shows how to convert gpt to mbr disk in Windows 10 by Brink. It mentions the clean option that you mentioned with diskpart but it also says to finish with convert mbr command. It doesn't mention anything about creating a primary partition like was mentioned earlier in posts above. Is the tutorial ive just mentioned for removable drives intended for USB flash drives or is that tutorial for something different? Could you link me to the correct tutorial for the procedure if there is one
      My ComputerSystem Spec

  10. Bree's Avatar
    Posts : 8,808
    10 Home x64 (1809) (10 Pro on 2nd pc)
       17 Dec 2017 #30

    sportsfan148 said: View Post
    I know Rufus uses GPT and recommends it for UEFI
    That's as maybe, but 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.

    Click image for larger version. 

Name:	MCT fail 0x80004005.PNG 
Views:	311 
Size:	11.7 KB 
ID:	168599

    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.
      My ComputersSystem Spec


 
Page 3 of 8 FirstFirst 12345 ... LastLast

Related Threads
Hi all, Having had a problem using the Media Creation Tool to create a bootable Windows 10 USB flash drive Ive decided to use the Media Creation Tool to download the Windows 10 ISO and then use Rufus to create the bootable USB flash drive. After...
Is it possible to discover the previous drive letter assignments on an old boot drive? I have a Windows 7 boot drive that previously was part of a system with 8 hard drives. I cloned the boot drive from this system and moved to a newer system,...
Hardware & Drivers Change and Assign Drive Letter in Windows 10 in Tutorials
How to Change and Assign Drive Letter in Windows 10 By default, Windows 10 will automatically assign an available drive letter to any connected internal and external storage devices. Windows progresses through the alphabet from A to Z to...
Solved Question About W10 Flash Drive in Installation and Upgrade
I am dual booting W10 and Ubuntu 14.04 on one computer and W7 and Ubuntu 14.04 on a Desktop. I have W10 on a Flash Drive that I made when I updated this Dell 960 small form 64 bit computer from W7 Home to W10 as a test about 8 months ago. I am...
Cannot assign a drive letter in Drivers and Hardware
Hi folk. I have an external drive where the electronics of the case has failed. I have switched the drive into my pc so that I can use it as an internal drive. The drive is still operational but I cannot see it listed in my drives. Opening up disk...
Our Sites
Site Links
About Us
Windows 10 Forums is an independent web site and has not been authorized, sponsored, or otherwise approved by Microsoft Corporation. "Windows 10" and related materials are trademarks of Microsoft Corp.

Designer Media Ltd
All times are GMT -5. The time now is 18:37.
Find Us