[SOLVED] Can I add an EFI partition to new SSD after I already installed Win 10

Jun 13, 2022
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So I just added an SSD to my HP PC with older standard HDD. Everythings running great and I want to format the old drive for storage but I see it has 3 partitions, mainly the EFI. Can I create a new EFI partition on the new SSD if I've already installed windows on it and what's the process? I checked and it's setup as GPT if that matters. Here's a screenshot of the disk management window,

 
Just trying to make sure what I need to do before going forward
Execute following from elevated command prompt, to create EFI bootloader on 500GB drive:
(if you get any errors, then stop immediately)
diskpart
list disk
select disk 1
list partition
select partition x
(select 447GB partition, x= 1 or x=2)​
shrink desired=500
create partition efi
format fs=fat32 quick
assign letter=H
exit
bcdboot c:\windows /s H:

Last message should be "Boot files created successfully".
Shutdown, disconnect 2TB drive adjust boot priorities in BIOS and try to boot into windows.
After that you can reconnect 2TB HDD and clean it using diskpart.

 

Darkbreeze

Retired Mod
You probably "can", but it's somewhat pointless really as the EFI partition is created by Windows during installation and is specifically purpose built for the configuration of that specific system. If you installed Windows on the SSD and there is no EFI partition on it then it's likely because you already had Windows including an EFI partition on the other drive and the system was tricked into thinking it did not need to create a new one. I'm betting that if you disconnect the HDD from the motherboard you will find that your Windows installation on the SSD will no longer boot.

Your best, and most recommendable path going forward would be to back up anything important you've got on either drive and then disconnect the HDD completely while you do a new, CLEAN install of Windows on the SSD. Then, afterwards, you can add the HDD back in, use disk management or a third party partition manager to delete the existing partitions on the HDD and then create a new single volume on it for use as storage or backups.

It would be helpful if you'd resize the screen capture of your disk management window to a size that can actually be read as it's too small to ascertain any details from as is.
 
Jun 13, 2022
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Of course, just after a get most things set back up how I wanted. So another question then... If I disconnect the HDD that has the EFI on it and use a USB installation drive, should it automatically detect the installation drive without the EFI partition present? This sort of thing is new to me.

Also, if I create a recovery drive and then reinstall windows with the installation drive, would the recovery drive set everything back up or do I still need to reinstall everything. Or what about a system image, is that the same as a recovery drive? Just FYI, all files are in dropbox, I'm only needing to backup the programs.

Thanks for your help
 

Lafong

Respectable
I cannot see detail on your pic; it is too small.

Can you boot your PC with the old HDD disconnected?

Yes or no.

I hope you had ONLY the SSD connected when you installed Windows to it. Did you or didn't you?

Imaging: first idea is that you shouldn't rely on a native Windows tool to do it.
 

USAFRet

Titan
Moderator
Mar 16, 2013
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Also, if I create a recovery drive and then reinstall windows with the installation drive, would the recovery drive set everything back up or do I still need to reinstall everything. Or what about a system image, is that the same as a recovery drive? Just FYI, all files are in dropbox, I'm only needing to backup the programs.
No, it doesn't work like this.
 
Jun 13, 2022
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Not sure why the image can't be expanded. Here's a link to it https://flic.kr/ps/2W8HmV

Yes I had the old HDD connected when I did the install but everything seems to be just fine other than the EFI partition situation. I honestly haven't tried booting without the HDD yet. Just trying to make sure what I need to do before going forward
 

Darkbreeze

Retired Mod
Try booting without the HDD attached. I'd almost guarantee it won't boot. And if there is NO EFI partition on the SSD, it absolutely won't boot in UEFI mode anyhow. For some legacy installations, it might, and that might be what has happened on your system but if your system supports UEFI installations with GPT partitions, then that is generally what you want. Legacy installations should only be used when installing on hardware that doesn't support a UEFI installation.
 
Jun 13, 2022
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I assume you mean the recovery drive doesn't work that way, correct? But what about the system image? From what I've gathered, that sounds to be the solution.
 

USAFRet

Titan
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Mar 16, 2013
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I assume you mean the recovery drive doesn't work that way, correct? But what about the system image? From what I've gathered, that sounds to be the solution.
You can't take a Windows System Image, then do a full OS install, and apply that System Image to the new install.

That 'Image' would wipe out the newly installed OS.

How much time do you have invested in this new OS install?
 
Just trying to make sure what I need to do before going forward
Execute following from elevated command prompt, to create EFI bootloader on 500GB drive:
(if you get any errors, then stop immediately)
diskpart
list disk
select disk 1
list partition
select partition x
(select 447GB partition, x= 1 or x=2)​
shrink desired=500
create partition efi
format fs=fat32 quick
assign letter=H
exit
bcdboot c:\windows /s H:

Last message should be "Boot files created successfully".
Shutdown, disconnect 2TB drive adjust boot priorities in BIOS and try to boot into windows.
After that you can reconnect 2TB HDD and clean it using diskpart.

 
Jun 13, 2022
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So now I just need to format the HDD but if I connect it again, will it remember the correct boot order? Or do I still need to fix the order first?
 
Jun 13, 2022
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Probably defrag is being run to complete the command.
You'll have to wait a bit.
I'm passed that now. The process timed out. I got it to go. Now I can boot from the SSD alone.

Now I need to reconnect the original HDD and format it. I went into the bios to make sure the boot order was correct but I'm not really sure how it should be.

Screen shot: https://flic.kr/ps/2W8HmV

Thoughts?
 
Last edited:
Jun 13, 2022
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@SkyNetRising ... So I went to delete the partitions but when I right click on the 2 Recovery partitions, it doesn't give any options except Help, if I right click on the EFI partition, it shows the options but everything is greyed out. Would I have messed something up by formatting the D: drive already before deleting the partitions?

I could just leave it how it is, everything is working great so if it aint broke, don't fix it.
 
@SkyNetRising ... So I went to delete the partitions but when I right click on the 2 Recovery partitions, it doesn't give any options except Help, if I right click on the EFI partition, it shows the options but everything is greyed out. Would I have messed something up by formatting the D: drive already before deleting the partitions?
It's fine. Disk Management will not allow deleting old EFI and recovery partition.
Use diskpart clean method instead.
Just don't clean the wrong disk. You have to select disk 2.

 

Darkbreeze

Retired Mod
Or, if unsure using that, the community edition, for free, of paragon partition manager works really well too. It maybe has a little bit easier GUI than some other options. I guess it depends on how adept you are with specific GUI's. Or if you prefer command line structure.
 
Jun 13, 2022
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Thanks, I went ahead and tried the paragon tool. It left the 2 recovery partitions just unallocated, not fully deleted but it did delete the EFI partition. I couldn't find a way to format the entire drive though, only format the main partition. I'm just going to leave it as is for now. There's more than enough space on that drive and everything is running amazing compared to what I was previously dealing with. I don't know why I didn't do this sooner.

Thanks for all the help! It's very appreciated

https://www.dropbox.com/s/3b60bic5ng1o07k/Screenshot 2022-06-14 150936.png?dl=0
 

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