VM Start with specific Date time (linux host/windows guest)

startvm.sh

#The directory that contains VBoxManage
vbox_path="/usr/bin/"

#This should be your VM name
vm_name="<YOUR_VM_NAME>"

#Use http://epochconverter.com to find the desired time
start_utc=1489325734

#DO NOT CHANGE ANYTHING BELOW THIS LINE

now_utc=`date +%s`
diff_utc=$((start_utc*1000 - now_utc*1000))

echo "START UTC:" $start_utc " DIFF UTC:" $diff_utc " NEW UTC:" $now_utc
cd $vbox_path
./VBoxManage setextradata $vm_name "VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled" "0"
./VBoxManage setextradata $vm_name "VBoxInternal/TM/TSCTiedToExecution" 1
./VBoxManage modifyvm $vm_name --biossystemtimeoffset $diff_utc
./VBoxManage startvm $vm_name

You can change $vm_name to "$vm_name" to fix issues with special characters like whitespaces in the name of the VM.