Workaround:
Use Ctrl+Alt+Delete (or Ctrl+Alt+Insert on Windows) to soft-reset the virtual machine, or restart the guest operating system by right-clicking on the virtual machine and selecting Restart Guest. This will not disconnect the standard I/O devices, such as mouse/keyboard/screen (MKS), or remote devices. The BIOS screen is displayed, and the boot order can be changed.
For virtual machines created on ESX Server 3.5, you can change the settings under Advanced > Boot Options in the Options tab of the Virtual Machine Properties dialog box to delay the boot sequence so that the MKS connection has time to be reestablished.