i can't download the os x mavericks from the app store i always get "We could not complete your purchase The product distribution file could not be verified. It may be damaged or was not signed"

In Finder menu > Go to folder... enter

/var/folders/

In one of the folders find com.apple.AppStore and delete that folder. Then relaunch AppStore and test.

From your Finder "Go" menu > "Go to folder"

Then enter...

Click on "Go"

Now you have to hunt a bit, follow the path in the screenshot in my first reply.

It may not be the pj folder on yours.

it didn't work for me .. please tell me an alternative .