No boot device found when you change the Boot sequence to Legacy mode

Follow the guidelines below to resolve the following error message:

The No boot device Found error appears when the Boot sequence is set to Legacy mode or the operating system is installed under Legacy mode. 

No boot device found error

The following error may appear after operating system installation: "No boot device found" (Figure 1). 
This error occurs when device bios boot sequence is set to Legacy mode.

Figure 1: No boot device found error

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. 

If the operating system is installed with UEFI before boot sequence is changed, the system can be recovered by changing Boot sequence back to UEFI.

If the operating system is installed with Legacy mode, the system cannot be recovered by changing the Boot sequence back to UEFI mode. 
Operating system reinstallation should be performed.

Follow the steps below to reinstall Windows 10 or higher:

1. From a power off state, power on the system and Press F2 at the Dell logo to boot into the BIOS setup menu.
2. Choose Boot sequence and change the option from Legacy to UEFI then click Apply in the lower right corner of the screen (Figure 2):

   
   Figure 2: Change Boot List Option from Legacy to UEFI in BIOS settings.

3. Choose Advanced Boot Options and disable Enable Legacy Option ROMs then click Apply in the lower right corner of the screen (Figure 3):

   
   Figure 3: Enable Legacy Option ROMs in BIOS settings.

4. Choose Secure Boot -> Secure Boot Enable and change the option from Disabled to Enabled. 
5. Then click Apply in the lower right corner of the screen (Figure 4):

   
   Figure 4: Enable the Secure Boot Enable setting in BIOS.

6. Click Exit in the lower right corner of the screen and wait for the system to reboot.
7. Reinstall the Windows 10 operating system.

Follow the steps below to install the Linux operating system:

1. Follow steps 1 through 3 from the steps above for installing Windows 10 (these steps are the same for a Linux install).
2. Verify the Secure Boot -> Secure Boot Enable option is Disabled in the BIOS (Figure 5):

   
   Figure 5: Disable Secure Boot Enable in BIOS.

3. Choose SATA Operation -> SATA Operation and change to AHCI mode (Figure 6):

   
   Figure 6: Enable SATA AHCI

4. Click Exit in the lower right corner and wait for the system to reboot.
5. Reinstall the Linux operating system.

Recommended Articles

Here are some recommended articles related to this topic that might be of interest to you.

• How to Enable Boot from CD or DVD Option with UEFI Boot Mode Enabled
• No Boot Device Found When You Change the Boot Sequence to Legacy Mode
• Resolving Legacy Boot Mode Issues on Newer Dell Laptops
• BIOS Settings to Allow PXE Boot on Dell Latitude Laptops