I would like to create a Mac OS X Yosemite virtual machine but unable to do that because of "no entry" sign.
Shut down the Virtual Machine. Make sure that the virtual machine is shut down. If it is in a suspended state, please run it and then shut down (Actions > Shut Down).
Open your virtual machine's Configuration > Hardware Tab > Boot Order > Advanced.
Add the following boot flag into the Boot flags field:
- Start the virtual machine.