This type of issue usually occurs when the computer attempts to hibernate. Hibernation writes the system state to the disk and then shuts the computer off, and because Deep Freeze would wipe out the Hibernation file when the power was cycled you could loose data.
To prevent this Deep Freeze sets configuration options that prevent the system from entering a hibernation state when Deep Freeze is installed. This can prevent computers running Windows 7 from entering sleep states as Windows 7 provides a new feature called Hybrid Sleep that combines both a normal sleep state and a hibernation type of sleep to save power.
To enable the abilty for a Windows 7 workstation to sleep you will need to disable Hybrid Sleep using the instructions below:
- Open Control Panel > Power Options
- To get to the advanced settings click on the "Change Plan Settings" link next to your power profile and then on the "Change advanced Power Settings" link.
- In the dialog that is shown the option is found in Sleep > Allow Hybrid Sleep, setting this option to Off will allow the workstation to sleep.