When I try and start the game up, it tells me that "You are missing a key file to run this game".
I also looked in my download history but it's not there.. I think there might be an issue with that download since I had grabbed it for free when PSN+ first came out, even though my version now is from the 2 free psn games when PSN went down. The only thing I have in my download history is the Fury add-on.
What can I do to fix this?
The Wipeout bundle (from the WBP) came with three items that needed to be downloaded. Those three items were the demo (full game, but most of the content is locked), the unlock key (to unlock all content from the demo) and the Fury add-on.
You can easily download the demo free from the PSN Store. The real question is do you still have the unlock key?
There were quite a few people that only downloaded the Fury add-on, believing that they didn't need the others to play the game.
I'm aware of all that. When they first offered the games for free, Wipeout offered a single link that prompted for all 3 downloads. I was playing the game fine until a little over a month ago.
This is a problem that others are having as-well. I've searched google but I haven't found a solution for this.
Have you tried deleting the Wipeout HD game data through Game Data Utility and starting Wipeout HD again to redownload the updates?