PS4 and Xbone install the whole game to HDD even if you have the physical copy, once installed the only reason it Complain about not enough space but won't. Learn how to manage your PlayStation®4 storage space and game save data If you would like to install the game to the PS4 system storage, you may need to delete Don't worry, you won't lose access to any deleted games — you can. Because of how the PlayStation 4 stores games, you must have at least the original file size of the game available in free space to install any update. Warfare because most other games still utilize file copying but do not.
This is a very annoying problem I have also encountered many times. For some reason it thinks you don't have enough space even when you clearly do. Sometimes it can refuse a <1mb app when you have about mb free. Or it can allow a <mb app when you have roughly mb free.
I don't think there is a real 'fix' to this.
Freeing up even more space should solve the problem. You can just uninstall a bunch of apps and see if it works again. Or you can clean your caches and other files you don't need (like the log mentioned by David Balažic) with an app like SDMaid or 1TapCleaner or whatever app you use. Cleaning cashes/tombstones/logs can easily free up a lot of space for you to install whatever app you like.
The problem will return though once you run out of space again.
the, arguably, best solution would be to have fewer apps installed (I don't like this but it's what works best for me) or buy an sdCard and install apps on sdCard (with the help of an app like AppMgr III or similar).
For those with a Samsung device that splits memory in Sdcard and USBStorage, you'll have to find a different way to actually put the apps on the external sd card instead of USB Storage. I believe I read somewhere it is possible by factory resetting phone and then choosing to install apps on sd or something like that but I am yet to try that.