error when logging in virtual box

[Paulo_ti]

Good morning, I had a virtual machine created that was working perfectly, turned off the machine and the other day when I was starting the same virtual machine appeared the error below. The operating system that the virtual box is installed is Windows Server 2008 64-bit. The version of vbox is 4.3.20. I really need help, below is the error:
Result Code:
RPC_S_SERVER_UNAVAILABLE 0x800706BA (0x800706BA)
component:
ProgressProxy
Interface:
IProgress {c20238e4-3221-4d3f-8891-81ce92d9f913}

[war59312]

Will the Windows install start up in safe mode?

Try disable audio?

Looks like others having same issue @ https://www.virtualbox.org/ticket/12064

Running Exchange by chance?

[mpack]

Minimum information needed for assistance.