After the security fix update in version 0.9.2.5, I immediately noticed that the disc caching (basic) is not working anymore. I tried to explain this in another thread but @Frederick probably didn't notice that. So I'm writing this in hope that the plugin author will notice this and take appropriate action.
Version 0.9.2.5 introduces a fault with basic mode disk caching. A cached page is now being prefixed with a nine byte text string. This text is inserted before the page expiry time and compressed page data is written.
What this means is that the page expiry time is never picked up successfully when the cache page is referenced. The page is always thought to be expired and cached disk pages are never returned. There is also a problem with decoding of the returned data.
Here is the original explanation and even a fix for the problem http://www.wmiles.com/2013/01/03/w3tc-cache-preload-for-version-0-9-2-5
@Frederick, if you read this I think you should fix this ASAP, since I guess many people were using the basic disc caching, including me.