Sudenly, it refuses to compile a sketch that was working ok, with messages like 'int (the variable)' previously defined here', ridiculous as it is the first and only declaration of the variable.
I must add that I copy and pasted the whole error messages list and it gives the same error for each definition ("redefinition of...").
Sometimes with other sketches, it suddenly gives error: ld returned 5 exit status, and sometimes buy just adding a Serial.println anywhere it is fixed.
Now I restored a copy of a sketch that I saved as soon as it was working, but now it can't be compiled.
I find posts from other users complaining about the latest version. I'm running 1.6.7.
I tried to install previous versions, like 1.6.6, 1.6.0, 1.5.8, some worked without altering the sketch but then it refused to connect to the COM port, even when it was clearly detected in Device Manager as the COM4.
All of this is frustrating.