[NUC] Can't Enable Legacy Boot in NUC BIOS

[FAQBot]

[NUC] Can't Enable Legacy Boot in NUC BIOS

The Legacy Boot setting in the BIOS can be grayed out for a number of reasons. You may need to check each option below before you can enable Legacy Boot. 

Note	Many products no longer support/enable the Legacy Boot setting in the product BIOS.  Confirm here if your model is included in the NUC Products Phasing Out Legacy BIOS Support before proceeding

After checking the above supported list, try the following to resolve any issues being encountered

Click or the topic for details:

Make sure that Modern Standby is not enabled in the BIOS (Legacy Boot is not allowed when Modern Standby is enabled).  If it is enabled, this needs to be changed to Legacy S3 Standby

1. Press F2 to enter the BIOS during boot
2. Go to the Secondary Power Settings menu:
   1. Advanced -> Power (in Visual BIOS)
   2. Power -> Secondary Power Settings (in Aptio V BIOS)

1. Set Sleep Type Support to Legacy S3 Standby
2. Press F10 to save changes and restart

Note

At the next restart after changing this setting, the following message will be displayed:  WARNING! A change has been detected in the BIOS Sleep Type support setting, from <last sleep type> to <new sleep type>. Dynamically changing the Sleep Type support setting between Legacy S3 Standby and Modern Standby is not supported and may require reinstalling the Operating System. Would you like to continue? Enter (y) for Yes to continue, or (N) for No for reboot. According to Microsoft, switching the power model isn't supported in Windows without a complete Windows reinstall. Changing this BIOS setting doesn't change the Windows power model.

Disable Secure Boot (Legacy boot is not allowed when Secure Boot is enabled)

1. Press F2 to enter the BIOS during boot
2. Go to the Secure Boot menu:
   1. Advanced -> Boot -> Secure Boot (in Visual BIOS)
   2. Boot -> Secure Boot (in Aptio V BIOS)

1. Disable Secure Boot
2. Press F10 to save changes and restart

Does the system contain an Optane™ memory device?  If the SATA mode is set to RAID or Optane Memory related, Legacy boot will not be supported.

Warning

The operating system will not boot if this setting is changed after the operating system has been installed Confirm if the product includes Optane™ memory and do not change this setting if it is currently active

1. Press F2 to enter the BIOS during boot
2. Go to the Sata Mode setting:
   1. Advanced -> Devices -> SATA -> Chipset SATA Mode (in Visual BIOS)
   2. Advanced -> Storage -> SATA Mode Selection (in Aptio V BIOS)

1. Set SATA Mode to AHCI
2. Press F10 to save changes and restart

Related topics

Does my NUC have the Visual BIOS or the Aptio V BIOS?

Modern Standby (Microsoft site)