Its predecessor, Cryptolocker Prevention worked great against Cryptolocker and I'd imagine if Cryptowall behaves like it then will thwart it as well. This one is easier to use because it's just one button. The only side effect is that a lot of installers execute directly from the Temp folder which will be broken. If an MSI package can be found (Java) or a way to extract elsewhere then execute from there, it's just a minor hassle. But if there is a poorly written installer like say Neat Scanner software or AutoCAD updates, it could get hairy. Software Restriction Policies can be designed that effectively do the same but you have better management over it in these cases. I have not played as much with the SRP though. Whitelisting is a lot safer than blacklisting in this case because the trojans will just find ways around blacklists.