BlueStacks 4 Hyper-V does not finish booting while Hyper-V is enabled I am using Windows 10 20H2, 64-bit, with CPU virtualization enabled.
I have enabled Virtual Machine Platform because I use Windows Subsystem for Linux. But I had not enabled Hyper-V when I installed BlueStacks.
I installed BlueStacks 4.0 via this executable: BlueStacksInstaller_4.260.0.1032_native_4176a437bc759281d8303dbcf40bdb72.exe,it automatically detects the settings of my computer and downloads the appropriate edition of BlueStacks.
After installation I started BlueStacks, and it starts fairly fast.
But I found the edition of BlueStacks I have installed is BlueStacks (Hyper-V), however I had not enabled it.
So I enabled Hyper-V in OptionalFeatures.exe, and restarted, and then I found out that it just won't finish starting up, it just stuck at displaying Starting BlueStacks Hyper-V, please wait.
The progress bar is very close to finish point, but it just refuses to go any further, like this:

Finally it said: Could not start the Engine.

I restarted the Engine multiple times and always succeeded in recreating the problem.
I then disabled Hyper-V and rebooted my computer, and I can use BlueStacks again.
However I also want to use Oracle VirtualBox, which requires Hyper-V.
So I uninstalled BlueStacks and downloaded the non-Hyper-V edition, tried to install it while Hyper-V is disabled, and it failed with error:

But Hyper-V is disabled:
PS C:\Windows\System32&gt; Get-WindowsOptionalFeature -Online | where {$_.FeatureName -match &quot;Hyper-V&quot;}

FeatureName : Microsoft-Hyper-V-All
State       : Disabled

FeatureName : Microsoft-Hyper-V
State       : Disabled

FeatureName : Microsoft-Hyper-V-Tools-All
State       : Disabled

FeatureName : Microsoft-Hyper-V-Management-PowerShell
State       : Disabled

FeatureName : Microsoft-Hyper-V-Hypervisor
State       : Disabled

FeatureName : Microsoft-Hyper-V-Services
State       : Disabled

FeatureName : Microsoft-Hyper-V-Management-Clients
State       : Disabled

I have disabled Windows Defender and I am not using any anti-virus software, my computer has 12 GiB RAM and its CPU is Intel Core i5 4430 @ 3.00GHz;
How can I use BlueStacks with Hyper-V enabled?
Yes, this is because I have enabled Virtual Machine Platform and it implicitly enables Hyper-V, because Hyper-V is a native hypervisor, as long as it is enabled Windows boots as a virtual machine and can only access the emulated CPU and can't access the physical CPU, the emulated CPU doesn't support VT-x, so as long as Hyper-V is enabled performance of hosted hypervisors will decrease.
And I found out that Windows Defender Device Guard is also enabled and it also implicitly enables Hyper-V.
So I used these commands in elevated cmd to truly disable Hyper-V:
bcdedit.exe /set hypervisorlaunchtype off
dism /online /disable-feature /featurename:VirtualMachinePlatform
reg add HKLM:\System\CurrentControlSet\Control\DeviceGuard /v EnableVirtualizationBasedSecurity /t REG_DWORD /d 0
shutdown /r /t 0

After that I can't open BlueStacks (Hyper-V), so I uninstalled it and installed the version without Hyper-V, which is faster because of VT-x.