Problem with ram macbook pro late 2013

[EstherM]

I have a macbook pro late 2013 with 8 GB of ram and since 3 weeks ago sometimes appears this message "Your System has Run out of Application memory" and until I don´t reboot the mac I can´t do anything even if I close all the apps I´m using. One thing I have notice is that when this happens iSat says that I have 4 GB of ram. What should I do?

 

[Meister]

This might help:
https://forums.macrumors.com/threads/1594921/