Make sure clean happens first and is finished, then execute other tasks with max parallelism . This is important as clean can be in the middle of deleting otherwise and then one,two or three could be creating files or dirs. If this happens or collides then you will get rmdir or rmfile errors inconsistently.

gulpfile.coffee

gulp.task "clean", ->
  gulp.src('dist', read: false)
  .pipe clean()
  
gulp.task "one", ->
gulp.task "two", ->
gulp.task "three", ->
  
gulp.task "default", ["clean"], ->
  gulp.start ["one","two","three"] 

http://goo.gl/6NVZku