compiling problem

Compiling stops 1/3 way through my sketch . But 1 day before it completed.

Oh dear.

A bunch of people have had IDE 1.6.x problems, including IDE crashes and bizarre compile errors. At least some of those problems seem to be caused by out-of-date executables that the IDE saves outside the IDE installation directory. Perhaps that is what is causing your particular problem. In such cases it appears that the fix is to delete or rename the old "Arduino15" directory and re-install 1.6.x.

On Mac OS X: /Users/(username)/Library/Arduino15

On Windows: C:\Users(username)\AppData\Roaming\Arduino15

On Linux: /home/(username)/.arduino15 (a.k.a. ~/.arduino15)