"Scratch disk full" but it is not

Hi all,

I haveI have more than 700 GB availbe but PS keeps showing this error of scratch disk full that drives me crazy and the only way to fix is to reboot the machine, so i have to save everything (if it lets me) and reboot 

The maximum file size I may work with is around 2GB nothing too big.

I have attached some screenshots of my sysytem etc

Most forums or pages on adobe or wider web are talking about how to cleanup and make more space which was not helpful in my case so any hints or ideas would be great.