Boot stuck on: '/dev/sda6: clean, 346072/9134080 files, 34705132/36529664 blocks'

What happend: I installed a windows 10 virual machine in virtualbox (vb) on Ubuntu 20.04 lts. I used it a little and then I tried to open the ubuntu file explorer, so that it would come before the vb window. Well, then vb stopped working, I could not turn off my windows virtual device, I could not close vb, so I tried to turn of my computer, but that was also not possible. Then I thought the only solutions would be a forced turn off (so holding the power button for 6 seconds), so I did that.
Now if I try to boot Ubuntu I see this on my screen: '/dev/sda6: clean, 346072/9134080 files, 34705132/36529664 blocks'.
I looked on the internet en saw people also having there boot stuck with the same line displaying. People gave solutions, they said that I had to open the commandline with ctrl + alt + f2 or f3 and type some things there, but if I try that there isn't opening any terminal. What do I have to do to fix this and make use of ubuntu again?

I have a duelboot Ubuntu/Windows 10. Windows 10 still works perfectely.