IDEA 8.1.3 : deleting outdated files taking forever on every make (> 30s)

I have a maven backed project (multi module).

Whenever I compile, the compilation goes quite fast, but a phase "deleting outdated files" takes a long time , even if I'm only compiling 1 file (using Ctrl+Shift+F9).
The cpu usage is low during this.

Is there anything to be done to speed this up ?