System extension

Try to disable SIP in recovery mode.

I can't disable SIP, just call Apple, the only way is to revert the installation of this beta 😟

I certainly didn't want to disable SIP on my Mac, but as I need VMware to work, I didn't have a choice. But hopefully, it works! Thank you!

I made it without reverting to the previous version.

Following those instructions should work for you too:
https://www.imore.com/how-turn-system-integrity-protection-macos

I found that you can allow just VMWare Fusion without disabling SIP. In recovery mode on reboot (⌘ - R), open Terminal and use the following command:

spctl kext-consent add EG7KH642X6

then reboot.

This specifically adds VMWare as an allowed system extension vendor.

EG7KH642X6 is the Team ID for VMWare. Other vendor Team IDs can be found here: https://docs.google.com/spreadsheets/d/1IWrbE8xiau4rU2mtXYji9vSPWDqb56luh0OhD5XS0AM/edit

I found this solution here: https://www.jamf.com/jamf-nation/discussions/27654/system-extensions-blocked-after-upgrading-to-high-sierra-10-13-4