So this has been posted here before by someone else, but I can't find the thread, credit for the upload goes to him/her.
The original upload however, has no instructions for the MAC version. Now for most of the files (that have keygens), it's pretty straight forward- install, run, and when the activation pops up, choose "activate via phone". put the code into the keygen, and then put the new code from the keygen back into the popup. nothing new here!
but for Color Efex Pro it's different! There is no keygen, and as far as I can tell this is one of the only working cracks for it on the net (it was the only one I could find). And here's how it works:
-Install and don't run it.
-Go to Unzip the [KG] file
-Go to applications/nik software/color efex pro
-Replace the ColorEfexPro app in that folder with the one from the zip file
-Go to applications/photoshop/plugins
-Delete both the NikEffectsPro.plugin file, as well as the config file. (It's important that you delete them first, rather than replacing them)
-Put the NikEffectsPro.plugin file into the now empty folder.
If you have any questions or need clarification on installations let me know, but I've only done the MAC version. Windows people will have to figure it out themselves (but there are instructions in the windows folder.
PS: This includes the following plugins:
Silver Efex Pro 2
Color Efex Pro 4
HDR Efex Pro
Sharpener Pro 3
Tested to work with Photoshop CS5 and Lightroom 3 (Doesn't work for LR4), and it should work with apeture too