CS4 is unsupported under Yosemite and doing an in place upgrade makes it even worse.
Is there a fix?
As I said, it’s unsupported and won’t be supported. You cannot blindly upgrade an operating system and expect old software to work with it.
You can try to uninstall, run the CC Cleaner tool and then reinstall it properly. If that doesn’t work, if you have a back up, roll back. If not. Wipe the drive and try a clean install. You’ll have a far better chance of getting things working properly.
Otherwise, if you have to have Yosemite, you’ll need to upgrade.
Since I work for a publisher, I have it on all my personal machines as well. I'll just use the Windows version from now onward. I know Adobe wants me to pay a monthly fee to use a program I purchased (three times), but I'm not interested in that.