A great concept but, in my professional experience, these Windows restore functions just aren't what they're cracked up to be. Much to my disappointment, they appear to have a very high failure rate - so much so that I have often simply turned them off. While I strongly suspect this problem may have something to do with some undocumented incompatibility with automatic defragmentation utilities, I haven't the time or interest to invest in the investigation. Hopefully, someone reading this will take up the challenge to finally figure this out. I simply caution my clients to regularly back up their data and to NEVER rely on these built-in features.

PS: By "undocumented incompatibility with automatic defragmentation utilities," I should explain that I always configure them to use defragmentation methods that have been optimized for VSS whenever appropriate but that doesn't appear to help.