One company I worked at the newer SQL Servers started taking forever to reboot the OS. The older servers didn’t take all that long. It finely dawned on us one day what it was.
Years earlier a sysadmin had added the Clear page file on reboot setting to a GPO which would require all the machines at the company to clear the page file when rebooting. Now when the servers has a Gig of RAM, and the workstations all had 256 Megs this only took a minute or two and no one noticed. However when us IT folks started upgrading our machines to 2-3 Gigs of RAM, and servers started getting 4-8 Gigs of RAM (this was 2004-2005 so that was an acceptable amount back then) the machines could take 30-60 minutes just to reboot.
We cleared the setting, and made sure that any machines which were rebooted in the next to days got a gpo update before the reboot and we were set.
Now if you work at a high security shop (DOD, NSA, etc) this probably won’t be an option for you which basically sucks, sorry. Not much you can do about it. If you don’t work in a shop which requires this setting do your uptime a favor and remove the setting. The odds of a page file from a server getting into the wide is pretty slim (possible, but pretty slim).
When it took an hour to reboot the SQL Server we pretty much never got approval to reboot. When a reboot would take 5-10 minutes they got a lot easier to get approved which meant that we could batch much more often.