UEFI Infinite loop

Tomax7 · November 2022

Hi, just purchased your product and wanted to convert my Dell Optiplex 790 with Windows 10 Pro to UEFI from legacy. Go through the steps and then upon reboot says "no bootable devices". Go back into BIOS to pick Legacy mode and reboot, then get a screen telling me to go into the BIOS and pick UEFI. Is there a way to roll back or what options do I have?

Tomax7 · November 2022

Guess I'm hooped. Dell website: If the operating system is installed in Legacy mode, the error message appears when you reboot/restart the system. The failure cannot be recovered by changing the BIOS setting back to UEFI. The operating system should be reinstalled.

wish I would have known this, or at least AOMEI would have something like this before I proceeded. My bad. Have backup and will restore, ironically from competition backup...

aiArtisan · December 2022

Thank you Tomax, for letting us know about this issue. You didn't say which product you used, nor which operation you attempted. I am guessing the product was Partition Assistant, and used the Convert MBR to GPT feature. If this is the case, I understand you tried to boot to UEFI setting after that, which UEFI setting did you try? Did you try both UEFI CSM, and UEFI non-CSM? I understand UEFI non-CSM is made for MBR disks, but it is still worth a try, given your situation. After that, you could try to reset UEFI settings to factory default. What boot repairs did you try? If you still cannot boot, I would recommend using LazeSoft to attempt boot repairs, link is below.

Please reply with several screenshots of the product you used, the feature you used, the resulting error afterward, your UEFI settings, and a list of the boot repairs attempted, thank you.

Great free tools from Aomei:

Create Partition Assistant WinPE USB:
Please add custom drivers, such as NVMe, if necessary

Great free tools not from Aomei:
LazeSoft - live USB boot repair

Ventoy - Bootable USB Creator

UEFI Infinite loop

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