If you are trying to update your copy of Call of Duty: Modern Warfare, you might run into an error when it comes to installing all of the changes. Luckily, there is a simple fix for that.
Because of how the PlayStation 4 stores games, you must have at least double the original file size of the game available in free space to install any update. Modern Warfare has a base file size of 60.68GB, with an additional 14GB download to cover the original day-one patch.
Unfortunately, that means you will need a total of around 120GB allocated just for CoD so you can have enough room for the entire base game, plus any additional files that have already been downloaded for the game.
This is a problem almost exclusively limited to Modern Warfare because most other games still utilize file copying but do not require the full size of the game on the designated storage for your console. For example, Monster Hunter World releases content updates frequently and never uses that tactic but still copies files.
It is likely that whatever is causing this issue is internally linked to CoD and not the PS4 system, which means there is less of a chance that this goes away any time soon. So if you want to keep running and gunning, you should make sure your system storage is free of any clutter before you try and install an update.