Under Parallels Desktop 9 for Mac, upgrading a Mac OSX guest VM to 10.9.3 (official) results in a 'black screen' upon reboot.
Multiple other people have identified this issue as well:
The issue appears to be due to the Parallels Tools guest video driver not being compatible with 10.9.3
I've managed the following workaround which allows the guest to boot (and "Shared Folders" work), but the video is limited to the default 1024x768.
I hope Parallels resolves this quickly. Based on the above posts, this has been a Known Issue since early April.
1. Configure the Guest to 'Select Boot Device on Startup'
> Guest -> Configure -> Hardware -> Boot Order -> 'Select boot device on Startup' is checked.
2. Boot the Mac guest OS into 'Single User' mode
> Start the Guest, hit 'return' when prompted to enter startup options, then indicate '-s' as a boot option
3. Mount the root partition 'read/write' by issuing the command
> Enter 'mount -o update /' on the command prompt once the guest has booted.
4. Delete Parallels tools video Kernel extension.
> rm -rf /System/Library/Extensions/prl_video.kext
5. Reboot the machine
> Enter 'reboot' on the command line
That should give you access to the VM, but the video limited to default (1024x768)