Normal shutdown of VirtualBox a few days ago, today found unable to boot my system when OS X 10.10. This may be the result of the recent frequent VirtualBox upgrades.

Advice:
Provide a snapshot of the Linux virtual machine that is normally performing major configuration or project work

Error message:
VirtualBox client COM failed to create
Caller RC: NS_ERROR_FACTORY_NOT_REGISTERED (0x80040154)

Try solutions:
Restart the computer;
Reinstall VirtualBox
Correct solution:
Access to the Internet caused by access problems.
Find my VirtualBox application is in/usr/local/bin/VirtualBox
Open the terminal operation failure directly, use sudo/usr/local/bin/VirtualBox can run. But this is inconvenient. You have to run from Terminal as root every time.
Find the solution on the VirtualBox website below:
The first step:
View permission information for/TMP directory:

/bin/ls -ld /tmp

The second step:

Sets the owner of the/TMP directory to root

chown root /tmp

Third part:

Change the access control permissions of the file owner and group, -s is to give suID permissions, ordinary users can also run as root permissions.

chmod ug-s /tmp

Step 4:

Grant permission to the/TMP directory RWX 777

chmod 1777 /tmp

Step 5:

Delete the old.vbox directory

rm -fr /tmp/.vbox-root-ipc/

Then start VirtualBox!