Reassign "C" to a different drive

Ctuck
Ctuck Member Posts: 6

Tinkerer

Thanks to help from this forum, I recently installed an SSD drive, mirrored my C Drive onto it and changed the boot sequence to boot from the new SSD which has been assigned the letter "E".  I would now like to reformat the old "C" drive and use it for storage.  however, because it contains a copy of Windows 10 OS, windows refuses to reformat it.  I also tried to reassign the drive letter from "C" to something else but windows will not allow that either.  What's the best way to proceed?

Answers

  • Larryodie
    Larryodie Member Posts: 1,748 Community Aficionado WiFi Icon
    Old fashion way, Go to the dos command prompt and type format E: 
    1. Open the Windows command prompt.
    2. At the prompt, type format and the appropriate drive letter, and press Enter . For example, if the hard drive you are formatting is drive E:, type format E:
    3. When asked if you want to erase all contents on the hard drive, type Y to proceed.
  • StevenGen
    StevenGen ACE Posts: 12,507 Trailblazer
    Ctuck said:
    Thanks to help from this forum, I recently installed an SSD drive, mirrored my C Drive onto it and changed the boot sequence to boot from the new SSD which has been assigned the letter "E".  I would now like to reformat the old "C" drive and use it for storage.  however, because it contains a copy of Windows 10 OS, windows refuses to reformat it.  I also tried to reassign the drive letter from "C" to something else but windows will not allow that either.  What's the best way to proceed?
    Just as an addition and if you can't format the drive in DOS then do a format externally with an adaptor. Also, are both drives showing in "Disk Management" as you can format the old boot drive from DM also. But and usually having both drives installed and connected, the PC will always boot from your old C:\ boot drive and not the new cloned drive and showing it as "E" drive. If all that doesn't work then your last resort is to take the old boot drive out and format it externally with a SATA to USB 3.0 adaptor as that is a very useful adaptor to have (you can get these adaptors with a combo M.2 and SATA to USB 3.0 will also be very useful for future system with M.2 drives) then format the old boot drive externally to either MBR or GUID (GPT).
  • Ctuck
    Ctuck Member Posts: 6

    Tinkerer

    OK, thanks.  I've confirmed that its booting from the new E SSD drive not  the old C.  I'll try to reformat in dos.
    Thanks again.
  • Larryodie
    Larryodie Member Posts: 1,748 Community Aficionado WiFi Icon
    format E:/q for a QUICK format. 
  • billsey
    billsey ACE Posts: 34,672 Trailblazer
    No! No! Don't format E:, since that is your boot drive!
    Whew, I hope I got to you in time... If not, just redo the whole procedure again. Then, disconnect the old drive and boot to the new one. If the system partition is still E: then boot from the install flash drive and use diskpart to remove the E drive letter and assign C instead, then reboot and verify you are booting from the new C. Once that is all done you can reinstall the old drive (it will likely come up as E: now) and use Disk Management to wipe all partitions then create a new data partition that uses the whole drive.
    Click on "Like" if you find my answer useful or click on "Yes" if it answers your question.
  • Ctuck
    Ctuck Member Posts: 6

    Tinkerer

    OK, now I'm confused again.  First I have confirmed that I'm booting from the new SSD drive which is drive "E".  I have no intention to reformat that drive.  What I want to do is reformat the old boot drive which of course also contains a copy of windows 10 and is designated as "C".  When I tried to reformat "C" from Windows using either the Disk Management app or another app within Windows Settings (can't remember exactly how I got there), neither will allow it b/c it contains windows software.  So my question again is 1) how do I wipe the "C" drive so I can just use it for storage, and 2) is there any reason to reassign the SSD "E" drive to "C"?  If so, why? and 3) how do I reassign drive letters?
  • Larryodie
    Larryodie Member Posts: 1,748 Community Aficionado WiFi Icon
    My bad as I didn't read correctly and assumed the boot was C:.
    I'm glad that you caught it. 
  • billsey
    billsey ACE Posts: 34,672 Trailblazer
    As I said, you do this best by first booting with the old drive disconnected. That should put the system partition for the new drive at C: and use the new drive exclusively for the full process. Once you are up and running in that environment you can reinstall the old drive and use Disk Management to wipe all partitions before creating one partition the full size of the drive and formatting it as your data partition, likely E:.
    Click on "Like" if you find my answer useful or click on "Yes" if it answers your question.