Precision 7520 - Install Win10 in UEFI mode with USB Stick

Question

Hi, my new laptop came with Ubuntu installed. Now I want to install Win10 from an USB Stick. I created the USB Stick following this guide: www.tekrevue.com/.../ To boot from the USB stick, I had to disable Secure Boot and enable Legacy Boot in the BIOS. When the Win10 installer showed me the partitions, it also said that it couldn't install Windows on that drive, because it was not a GPT partition / not GPT compatible. Only after I removed all exisitng partitions (including the DELL EPS partition - which might have been a mistake?), I could repartition the drive successfully and install Win10. Now I wanted to switch back to UEFI Boot in the BIOS, but this doesn't work: When I switch to UEFI and click on 'Add Boot Option', a message comes up saying 'File System Not Found!'. After that, the system doesn't reboot anymore unless I switch back to Legacy Boot. So I am kind of stuck - what could be the problem? How could I boot in UEFI mode from the USB stick? Or is there a certain setting in the BIOS I am missing? Thx for every hint! Oliver

jphughan · Accepted Answer

Use a better tool to create a UEFI-compatible stick. I recommend Rufus: https://rufus.akeo.ie/.

Alternatively, if you installed Windows 10 Creators Update, there's an MBR2GPT utility you can run that will perform an in-place conversion of a Legacy BIOS setup (with an MBR drive) to a UEFI-compatible setup with a GPT drive. You run that first, then reboot and go into your BIOS to switch it to UEFI mode, because the system won't boot AGAIN until you make that change. You would then be able to turn Secure Boot on.

Ingrid1987 · Accepted Answer

Hi, JOLIVERP.

As suggested, you can convert MBR-format system disk to GPT in Windows 10 version 1703 (Creators Update) or later with the help of MBR2GPT utility. It will perform a in-place conversion.

Step 1: boot from the installation USB drive. Then press + to open Command Prompt.

Step 2: Type "mbr2gpt /convert /disk: n" to start the conversion. "n" is the number of disk that you want to convert.

You can do the installation then. Remember to switch the firmware to boot to UEFI mode after conversion. For more matters you need to pay attention to, you can visit MBR2GPT Windows 10.

If you have another USB stick around, you can make a bootable media that has MBR to GPT conversion tool installed to convert MBR to GPT without data loss. Good Luck.

JOliverP · Answer

I could solve it: The tool I used, did NOT create an UEFI USB image. I tried 'Rufus' and that worked like a charm!

JOliverP · Answer

ok thx a lot for your help! This is also very good to know.

JOliverP · Answer

ok thx a lot for your help! Using Rufus it worked like a charm :-)

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