Windows 10 + Virtualbox 6 + Linux kernel 5

[JarekPT]

Hello

Short story:
I used VirtualBox at Win7 with a couple of Linux VM and they worked fine.
After moving to Win10 problems appeared VERR_SUPDRV_NO_RAW_MODE_HYPER_V_ROOT
Then I installed Hyper V and it helped but only in case of my old VM based on RHEL 7 and CentOS 7 (kernel 3.0)

When I tried to use Linux equipped with new kernel 5.0 (Fedora 30) after boot loader start VM froze.
I tried to start RHEL 8 and Fedora 30 installer to create new VM and than after bootloader VM froze also.

[mpack]

After moving to Win10 problems appeared VERR_SUPDRV_NO_RAW_MODE_HYPER_V_ROOT
...

Which means that Hyper-v is installed and conflicts with VirtualBox.

Then I installed Hyper V and it helped but only in case of my old VM based on RHEL 7 and CentOS 7 (kernel 3.0)

The Hyper-v platform was already present. Probably all you installed was some kind of UI or additional modules.

Which build of Win10 did you move to? Recent versions of Win10 Pro use the Hyper-v technology as the basis for many more features than the obvious Hyper-v flagged ones. See FAQ: I have a 64bit host, but can't install 64bit guests.