So I've read multiple places that it is impossible to run Pages '09 on Mojave. It will start, but when you try to create or open a document it will fail. A lot of people have reported this, but I could not find any solution online. So I decided to do some digging. I noticed that it would work the first time i started it. I was able to create and save a document. But when I tried opening it, it would fail. And it would continue to fail. So I tried deleting the "com.apple.iWork.Pages.plist"-file, and I was once again able to open a document. Once. And of course all my pages settings had gone. But now I knew something in the plist file was causing the problem. After more digging, I found out that Pages would fail to load the document as long as the parameter "<key>NSWindow Frame SLPublicationWindow</key>" existed. So to get Pages 09 working on Mojave, all you have to do is type Code: defaults delete com.apple.iWork.Pages "NSWindow Frame SLPublicationWindow" in the Terminal. This will remove the affected section of the plist file, but keep all the other settings. Note that this command must be run before every opening/creating of a document. So it's not a perfect fix, but it works! And for me, who has not updated to Mojave because of this incompatibility, can finally update.