Windows 10: Unable to assign drive letters after Win10 Upgrade

Wow! The partitions are keeping their assigned drive letters even after a reboot. What kind of sorcery is this?!? hahaha. I don't have a clue what went wrong in the first place. I am shocked. Hats off to you topgundcp!!

 

Great to hear. Now you can do the same for disk 3 & 4. Also delete EFI System partition. Another thing I notice that your disk 5 is 4TB disk and diskpart did not show it as a GPT and that is confusing.

Well it's not. Lots of people don't realize that third party partition managers work well with MBR type disk. With GPT disk, they can mess up real good and Windows could not determine what type of partition you have. With GPT, partition types such as Recovery, EFI System, MSR reserved ... each has a long hex number ID (GUID) and somehow got corrupted by Mini Tool. What we did was to set the id back to a "Basic Data Disk" so Windows will recognize it.

 

I know its not sorcery ;-), I really do appreciate you sharing the knowledge though. I have already done that to my other drives and I have the drive letters reassigned!

Yea the 4TB disk is a MBR disk. I haven't switched that one over to GPT yet. Is that not supposed to be possible?

Also, What are your thoughts on resizing the partitions to use up the space (however small) that was freed up by deleting the EFI partitions? I know that the Paragon Hard Disk Manager can do that fairly easily. It also has a feature to "convert" a disk from MBR to GPT. I think I tried that one on the 4TB disk and it didn't work... haha.

 

MBR only supports a partition size up to 2TB so I don't understand how you got the whole 4TB partition with MBR disk.
Now, with the EFI System partition deleted, you can not use disk management to extend it but to use Mini Tool, paragon etc...
With Mini Tool, right click on the partition->Move/Resize. A windows will popup, click and hold then drag to the left where the unallocated partition is (deleted EFI System) then again move the mouse to the right edge of the partition until you see 2 vertical bars, drag it to the right to extend the wholde disk, click Apply to commit the change. Do it with disk 1 first.

 

I am currently resizing disk 1 right now and it is taking forever. 2 hours and 45 minutes remaining for just the one disk.. haha I don't need the extra 200MB for the drives THAT bad. I will let this one finish so I don't mess anything up though.

I have no idea how the 4TB drive is a MBR disk haha. That's just the way that it was when I got it hahaha. I would like to wipe that one (since it is a backup disk) and change it to GPT and then back everything up again at some point.

Thanks to your help I am thinking that after a little bit more tinkering with my DAW software, I will be able to copy this cloned disk back to my main SSD, and be completely committed to Windows 10! I really do love Win10 and enjoy the UI changes like bringing the start menu back, and I'm excited for all the new improvements for Gaming. I ditched the Xbox One and went back to PC only. The Xbox App lets me still hang with my friends that still have Xboxes...