There are several reasons to use UEFI instead of BIOS. I won't go into details regarding that. But there are some cases when you already have a fully functional Windows installation running on BIOS and you don't want to start all over again. Sadly, there
are no tools that performs this job. And I found there is not too much documentation regarding how this can be performed either, or even how this should work. Since after some digging and trial-and-error I was able to perform the operation, I will post the
instructions for anyone who needs it.
If you have any doubt, feel free to contact me. I will answer whatever (and whenever) I can.
Convert a Windows 7/8 BIOS (MBR) installation to UEFI (GPT) without moving, copying or loosing data.
Steps were performed on Windows 8. Some steps in Windows 7 may have different menus, but the options and results are the same.
There is an Easier way!
Use a Backup tool Make a backup of your current Win8 system, (i used Acronis, but Ghost and other should work.
Using a bootup tool (acronis boot disk, or other usb/ODD startup tools) Format the disk in GDP.
Then adjust your bios settings for UEIF Start-up.
Install Fresh copy of Windows 8, or Windows 7* on the newly formatted Hard Drive.(Check the BIOs for a UEIF Startup option for your installation media there should be two boot options for your media now).
After Windows has installed, Check Disk Manager to see that you have the 100mb EFI partition.
Then use your backup tool to restore your original Windows installation over the new system. Making sure to uncheck any options for restoring the "MBR" .
Bam ya done.
*Like many people, i don't have a Windows 8 install disk, So i used a Windows 7, install disk, then used my Windows 8 install files to upgrade the newly installed Windows 7. This worked because the Windows 7 install disk was x64.
Make sure there is enough space before your main partition to create the two partitions in step 13. I had only 100MB and I got stuck there.
I was able to shrink and move my main partition thanks to a live-CD I had lying around, and complete the instructions successfully.
Well, this command simply does not work in W7 x64, there is no such syntax:
bcdboot c:\windows /s s: /f UEFI
Ended up copying the EFI boot files by hand - 3.6 Recreate the Boot Configuration Data from
and while booted from Win7 x64 SP1 DVD (non SP1 DVD hanged on Dell Vostro 3560) I simply rebuild bcd with bcdedit /rebuildbcd
Used this guide and worked perfectly despite some typo on step 4. Revised! :D I hope I helped others!
Regarding step 6 of Prerequisites:
what should I do if I have Windows 8 installed at the disk as a 1 partition?
I got stuck at step 13 as well. Please make a note at the top of your guide that lists the minimum required size of the System Partition. You mention it's usually around 1GB. I am on a default Windows 7 Ultimate installation and it is 100MB. I had to do a system restore before I even finished your guide.
Also, thanks for the info and your hard work!
@DarkKewlz: that would assume that you have third-party apps and enough additional storage. I never hard that scenario thus I wouldn't know if it works. But thanks for the tip.
@_-TaLSoftware: Haven't find that scenario. I just added a note to avoid such issue. Thanks!
@scerazy: thanks for the info on W7. Please feel free to edit and add info!
@daniyo27: thanks for the revision!
@rxulan: Are you sure you don't have a MSR partition? Anyway, you can "move" the Windows installation partition using some tool like Easus Partition Master (free) to create empty space at the beginning. Good luck!
@Orkalass: I just added a note. I'm sorry for your troubles. Please notice that you can move the W8 partition using some tool like Easus Partition Master to create empty space at the beginning. Good luck!
Sorry for the long post. This worked as advertised for my system, which came with Win8 preinstalled, except for one minor issue: my Recovery partition was broken after the procedure. It still shows up under diskpart and Disk Management, but I cannot use (for example) Settings->General->Refresh Your PC without an error indicating that files are missing. Same goes for Resetting the PC and Automatic Repair, etc, even when starting them under Advanced Startup with reboot required. So, it’s either a hosed Recovery partition or the OS is no longer able to access it.
I then found out the hard way that the System Repair Disc is not fully functional without a working Recovery partition – for one thing, most folks, myself included, cannot boot into UEFI mode from the DVD drive. Even after copying an ISO of the Repair Disc to a USB drive, which did allow boot into UEFI, I could not run the above mentioned Refresh/Reset/Auto Repair etc. without a working Recovery partition.
Luckily, I had taken a bare-metal Ghost image of the machine when it was brand new. My solution was to restore this pristine image to a spare machine, and then run Create a Recovery Drive to make a fully functional Recovery USB, which includes all of the functionality of the Recovery partition (the USB needs to be at least 16GB, I believe). I can now boot this USB in UEFI mode to run Refresh/Reset/Auto Repair, etc, on the machine that was converted to UEFI. The useless Recovery partition can then be deleted, and its space added to the C drive (using Disk Management), which is what many would prefer anyway (hence the Delete the Recovery partition option that appears when creating the Recovery USB).
On my spare machine, I tested a technique for restoring a working Recovery partition on the PC, for those who prefer that to a separate Recovery USB: on the machine that was converted to UEFI using the above technique, make a Ghost backup of the C drive (main Windows 8 OS drive) only. Then boot into the Recovery USB (in UEFI mode) and run Reset Your PC, which will wipe everything and reinstall the OS (in UEFI mode, if the USB was booted that way), including a working Recovery partition. Then boot Ghost and restore the C drive, and the onboard Recovery partition should now work. A lot of trouble, and some risk, plus the loss of C drive space, so it’s probably better to use the separate Recovery USB – just be sure to back it up somewhere. Other backup SW can be substituted for Ghost so long as it can back up a single partition instead of the entire drive.
If there is some way to re-write the steps above to preserve the Recovery partition, that would be welcome, unless my system was odd and no one else had Recovery Partition issues. My suggestion is that folks make a full Recovery USB in addition to Carlos’s recommendation to create a System Repair disc. This can then be substituted for the repair disc in Step 5 above. Instructions on making the Recovery USB can be found here:
D-FENZ edited Revision 9. Comment: Added recommendation that the recovery drive be backed up to USB