[SOLVED] SSD not detecting in UEFI mode but working fine in legacy mode

Jan 14, 2021
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I have a hp laptop for which I have upgraded to an SSD drive. I have installed the windows in the SSD drive in legacy mode. After that when I put my old HDD in a cady and insert in it and turned on the PC it booted from that drive. (I haven't formatted it yet). Then I removed it.

So, for now, I have windows running on my SSD, which is not detected in the UEFI boot menu but is available in legacy mode. If I turn off legacy mode, the system shows no OS found. But t works fine when the legacy mode is on.

Let me know how can I fix this issue, or it is just normal.
 
Solution
It is perfectly normal. Legacy (CSM) and UEFI boot modes does not mix. If you have UEFI enabled in BIOS, then OS must be installed after BIOS switching to UEFI. OS, installed in legacy mode is not recognized by BIOS when UEFI is enabled. That is by design. You have a choice - remain with BIOS in Legacy/CSM mode or switch BIOS to UEFI and reinstall Windows.

If drive with Windows installed in legacy/CSM mode is not recognized then partition table on drive must be wiped out with partitioning tool before using this drive for OS installing in UEFI mode. Switch BIOS back to legacy mode. Download USB bootable recovery OS image (Hiren’s BootCD, SystemRescueCD etc.), put on USB stick, boot from it and wipe mentioned SSD out...
Jan 14, 2021
2
0
10
Hi, thanks for the reply.
When I turn off the UEFI mode, my laptop doesn't detect SSD. and hence I can't move forward to install windows.
What will the possible issue?
 
It is perfectly normal. Legacy (CSM) and UEFI boot modes does not mix. If you have UEFI enabled in BIOS, then OS must be installed after BIOS switching to UEFI. OS, installed in legacy mode is not recognized by BIOS when UEFI is enabled. That is by design. You have a choice - remain with BIOS in Legacy/CSM mode or switch BIOS to UEFI and reinstall Windows.

If drive with Windows installed in legacy/CSM mode is not recognized then partition table on drive must be wiped out with partitioning tool before using this drive for OS installing in UEFI mode. Switch BIOS back to legacy mode. Download USB bootable recovery OS image (Hiren’s BootCD, SystemRescueCD etc.), put on USB stick, boot from it and wipe mentioned SSD out completely, including partition table. Then you can switch BIOS to UEFI mode and continue with Windows install.
 
Solution