Today I am discussing the default processing behavior for Group Policy scripts. Microsoft changed the default behavior of Group Policy startup and logon scripts processing from synchronous to asynchronous starting with Windows Vista and Windows Server 2008. This behavior is the same in Windows 7 and Windows Server 2008 R2. I’ve recently read some confusion regarding this policy setting.
Computer Startup Scripts:
The default processing behavior for computer startup scripts is asynchronous. Asynchronous scripts processing is when computer startup scripts no longer wait for the previous script to complete before starting the next startup script. Versions of Windows prior to Windows Vista defaulted to synchronous processing. This behavior can be changed by reading from the following locations, in the following order.
Key: HKEY_LOCAL_MACHINESoftwareMicrosoftWindows NTCurrentVersionWinlogon ValueName: RunStartupScriptSync
Key: HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionPoliciesSystem ValueName: RunStartupScriptSync
User Logon Scripts:
The default processing behavior for Group Policy logon scripts is asynchronous. However, this behavior can be changed by reading from the following locations, in order.
Key: HKEY_CURRENT_USERSoftwareMicrosoftWindows NTCurrentVersionWinlogon ValueName: RunLogonScriptSync
Key: HKEY_LOCAL_MACHINESoftwareMicrosoftWindows NTCurrentVersionWinlogon ValueName: RunLogonScriptSync
Key: HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionPoliciesSystem ValueName: RunLogonScriptSync
Key: HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionPoliciesSystem ValueName: RunLogonScriptSync
User Logoff/Computer Shutdown:
User Logoff and Computer Shutdown Group Policy Scripts always process synchronously.
Customers are noticing timing issues with their computer startup scripts when using Windows 7 and Windows Server 2008 R2. Yes, this is true because the default behavior changed to run these scripts asynchronously. If you relied on the previous behavior, then you need to configure computer startup scripts to run synchronously. Unfortunately, this is where some confusion surfaces.
You’ll soon notice that Windows does not include a policy setting to enable computer startup scripts to run synchronously, or does it? Yes, it does; however, not so intuitive. I’ve had some GP administrators break out the nice search feature in the Group Policy Management Editor and search for the keyword synchronous—this is not going to return the information you are seeking. The policy setting to enable this does not include the word synchronous in the explain text or in any other portion of the policy. You need to configure the Run startup scripts asynchronously policy setting to disabled to force computer startup scripts to process synchronously, which is the default behavior prior to Windows 7 and Windows Vista.
Hopefully, this will clear up any confusion with how Windows 7 process computer startup scripts and explain how to restore the older behavior.
– Mike Stephens