I also struggled a lot with this issue. The answers in this thread were helpful but were not enough to resolve my error. You will need to disable Hyper-V and Device guard like the other answers have suggested. More info on that can be found in here.
I am including the changes needed to be done in addition to the answers provided above. The link that finally helped me was this.
My answer is going to summarize only the difference between the rest of the answers (i.e. Disabling Hyper-V and Device guard) and the following steps :
Delete the following registry settings:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA\LsaCfgFlags HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\DeviceGuard\EnableVirtualizationBasedSecurity HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\DeviceGuard\RequirePlatformSecurityFeatures
Important : If you manually remove these registry settings, make sure to delete them all. If you don't remove them all, the device might go into BitLocker recovery.
Delete the Windows Defender Credential Guard EFI variables by using bcdedit. From an elevated command prompt(start in admin mode), type the following commands:
mountvol X: /s
copy %WINDIR%\System32\SecConfig.efi X:\EFI\Microsoft\Boot\SecConfig.efi /Y
bcdedit /create {0cb3b571-2f2e-4343-a879-d86a476d7215} /d "DebugTool" /application osloader
bcdedit /set {0cb3b571-2f2e-4343-a879-d86a476d7215} path "\EFI\Microsoft\Boot\SecConfig.efi"
bcdedit /set {bootmgr} bootsequence {0cb3b571-2f2e-4343-a879-d86a476d7215}
bcdedit /set {0cb3b571-2f2e-4343-a879-d86a476d7215} loadoptions DISABLE-LSA-ISO
bcdedit /set {0cb3b571-2f2e-4343-a879-d86a476d7215} device partition=X:
mountvol X: /d
Restart the PC.
Accept the prompt to disable Windows Defender Credential Guard.
Alternatively, you can disable the virtualization-based security features to turn off Windows Defender Credential Guard.