The following two options will help ensure your virtual machine does not become corrupted.
Do not let the laptop go into sleep mode, do not use a screen saver, and do not close the laptop lid while the virtual machine is running. Any of these actions can cause the virtual Engineering Station's database to become corrupted and unusable. Turn off sleep mode in the laptop's power options if at all possible (if allowed by your company's policies).
Run the following command on the host to preserve the state of the VM (where VM NAME is the name of the virtual machine (the DeltaV virtual Engineering Station) running on this laptop).
C:\Program Files\Oracle\VirtualBox\VBoxManage.exe setextradata VM NAME GUI/DefaultCloseAction SaveState
Reboot the virtual machine and the host to ensure it is active.