In order to troubleshoot maintenance window issues in servicewindowmanager.log it would be useful to know what the 'type' refers to (e.g. updates, task sequence etc):
OnIsServiceWindowAvailable called with: Runtime:1, Type:4 ServiceWindowManager 27/05/2015 09:18:22 7716 (0x1E24)
I've seen type 2, 4 and 6 mentioned in the logs
Thanks
David