After shutdown can not run guest VM

[LuBu]

Hello,

I have tried virtual box on my old laptop a few weeks ago and everything was working fine. I've installed it on my "new" computer, but I'm having issues.

First I've installed vbox 7 (latest version), I ran ubuntu installation, and it was working fine. After I shut down my (host/actual) computer, I could not start the ubuntu VM.
I uninstalled vbox 7 and deleted (I think) everything associated with it. After that I installed vbox 6, hoping it would resolve the problem.
Again I installed ubuntu, it was working fine, untill I shut down my PC. The same problem occured, I can no longer run the the ubuntu VM.

I disabled hyper-v, disabled WSL, task manager - virtualization is enabled, restarted the PC a bunch of times...

This is the error I am getting:

Failed to open a session for the virtual machine ububu.

The VM session was closed before any attempt to power it on.

Result Code: E_FAIL (0x80004005)
Component: SessionMachine
Interface: ISession {c0447716-ff5a-4795-b57a-ecd5fffa18a4}

Attaching VBox.log (first log file on the left (44-18))
Attaching VBox.log.2 (last log file on the right(55-40))

Thank you for helping.

Edit

I've started vbox as admin, and now it works. The first time I started it I didn't run it as admin. Even though it's working I would still ask for clarification why this problem occured (is occuring / not working if not run as admin)

[scottgus1]

As a rough guess so far, the failure to run the VMs after a host reboot may indicate a failed install of Virtualbox.

1. Uninstall Virtualbox and reboot.
2. Go to "C:\Windows\System32\drivers", look for any files called 'Vbox*.sys' (there could be up to 5) and delete them.
3. Reboot again.
4. If you have any 3rd-party security or anti-malware software, disable the living daylights out of it for a moment.
5. Reinstall Virtualbox using right-click-Run-As-Administrator.