Apps not opening, everything going wrong :(

[theRAMman]

Mac Mini Late 2015
Yosemite 10.10.5

The last couple of days, everything has gone a bit t*ts up - I can no longer open many of the core apple applications, iPhoto, Safari ect. The app will bounce in the dock but then disappear. In the case of Safari, it'll open up a page but then dissapear within a few seconds. My disk is apparently full, but deleting things seems to have no effect - I cannot open iPhoto to delete any of my pictures.

When I do try and move stuff to trash, instead of simply moving it'll give me a box telling me the file will be deleted immediately, which has never happened before. The problem doen't fix with restart.

Please help.

 

[JohnDS]

Boot into recovery mode by booting while holding down the command-R key combination. Go to Disk Utility. Highlight your drive on the upper left (it will be the brand and size of the drive). Go to the bottom right and see what it says under "S.M.A.R.T. Status". If it is anything but "verified" your drive is dying and needs to be replaced.

Assuming it is "verified", now run "repair disk". Once that is done, click on Macintosh HD (or whatever the name of your drive is) in the next line below your drive brand, and run "repair disk" again.

Report back here with the results.