I had this happen when I set passthrough on a graphic device that was being used on one of my VMs. Once I booted the VM that used the graphics card the screen changed. You might check what PCI devices you have set to passthrough and disable one at a time to identify the culprit.
For others that don't have a Web UI and cant SSH. This is one way to disable ESXi passthrough devices.
1. Boot with a debian or ubuntu live cd
List your drives / partitioned: Open a terminal window
2. type parted -l
Mine was sda5
3. mount /dev/sda5 /mnt
4. ls /mnt/
5. cp /mnt/state.tgz ~/
6. cd ~
7. tar xvf state.tgz
8. tar xvf local.tgz
So, you get an etc folder now. Go to /etc/vmware
9. nano esx.conf
10. Find /device/<PCI_ID>/owner = "passthru".
Replace passthru with vmkernel.
11. Save the file
Now let’s copy the file back to the mount point, but first we have to recreate the archive.
12. tar czf local.tgz etc/
13. tar czf state.tgz local.tgz
14. sudo cp state.tgz /mnt/
Thank you. You saved me.