Wait, Shadowcopy is getting used again?
I even had to create my own scripts after Microsoft DELIBERATELY crippled it somewhere around Windows 7 SP1 or SP2 - they did not touch it for servers, but they removed some command line options from vssadmin and forced a config which clears up shadowcopies after 7 days, no matter what you configure. Most importantly they removed the UI to configure it, the right-click-volume-configure-shadowcopy option which is still there on servers.
And NOW, I read "4-hour frequency", which is coincidentally my default setting from the scripts... Although a difference: Ever four hours yes, when older than two days only keep one per day, when older than 8 days keep only even days (of the month), when older 16 days keep only every fourth day (of the month). Limit is what you configured, unless above mentioned "Windows Professional and Home limit" catches you. (Another reason to use the server version of Windows...)
Oh, and I forgot to mention: This is one of the good working features of Windows, since Windows XP/Server 2003. And what does Micros~1 do? Everything else which less important unless you are 110% Marketing Public Relation Customer Experience Propaganda Department controlled.