What’s the difference between the fast startup policy and changing Hiberboot?

The key distinction is that this policy may control whether users can choose Fast Startup, rather than enforce that it is off. Setting “Require use of fast startup” to Disabled can mean the policy is not imposing a setting, so Windows or the user’s existing configuration still determines whether the feature is available.

That is different from explicitly setting the relevant Hiberboot value to disable the feature. Check the ADMX policy’s description and registry mapping for the Windows version you manage, then verify the resulting value on a test device. Policy labels can be easy to misread.

Think of the policy as a constraint on the setting, not necessarily an on/off switch. If the policy is not configured, it may leave the choice alone. If you need a definite disabled state, deploy the registry setting that represents that state, or use another supported management setting that explicitly disables Fast Startup.

Test the result after policy refresh and a restart, and check the effective registry value. Also confirm you are targeting the right devices and that another policy is not setting it back.

For the “why does Disabled do nothing?” part, look at the policy’s ADMX definition. ADMX files are XML, and they show which registry value a policy writes and what its Enabled and Disabled states mean. Some policies only write a value when enabled, so Disabled and Not Configured can effectively leave the setting untouched.

That explains the apparent mismatch without making the policy decorative. It may be useful for enforcing one direction while offering no explicit opposite state. Verify the exact mapping in the template installed in your environment.

If the goal is a real shutdown at the end of the day, test the actual behavior instead of relying on the policy label. A registry deployment that explicitly disables Hiberboot is one route, but make sure the value is applied consistently and check whether hibernation settings or other management policies affect the result.

Keep the change scoped to a test group first. Then confirm the setting after a policy refresh and check what happens during shutdown and the next startup.