Re: Something doesn't add up here...
I've never seen a crypto virus that renames the extensions. All I've encountered append a new extension. For example .zip would be come .zip.zzz. Can you give an example of one that doesn't rename files?
At any rate - using an incremental forever backup solution with only 1 version is a bit silly and prone to fail, if you get a file corrupted you're screwed from restoring it.