That file should be inside the application package, in the Required folder.
If that is missing, then your application install is damaged.
Well, how to fix it? I have the same problem here on a MBP.
Uninstall and reinstall the app to replace the missing files.
I was afraid it was going to be that. So
a) I have to entirely reinstall an almost 1GB top notch software because some few KB's are missing.
b) I don't know what I caused this in the first place so no guarantee it'll keep blocking my workflow.
Not that sharp if you ask me.
No, you have to uninstall and reinstall because something is wrong with your disk and caused files to disappear, or something on your system has randomly deleted files that are never supposed to be altered after the application installs.
And you are reinstalling so you can use your software.
But you should also be checking the disk and the rest of your system to figure out what caused the damage in the first place.
So there's something wrong in my whole system, where I'm using all kinds of different tools (big and small tools) for my various projects without a single hitch... but somehow photoshop has encountered a problem within his own set of files.
Again, a problem that photoshop error checking capabilities shows as a single file missing, which one would thing that's like a 5 min solution, but no. The entire monster needs to be reinstalled.
You understand my login right?
You are missing a file that should not be missing, ergo there is something wrong with your system that deleted a file that should not be deleted.
You might also be missing more files, but we don't know yet.
That file gets installed with the app, there is no reason for it to be missing, so no separate install or copy of that file.
Your system has a clear problem. Because of that, you will need to reinstall Photoshop to get all the required files back.