troubleshooter

1. A worker whose job is to locate and eliminate sources of trouble, as in mechanical operations.
2. A mediator skilled in settling disputes especially of a diplomatic, political, or industrial nature.

Person specializing in finding problems and solving them. Troubleshooters are often used in organizations to clear up difficulties.

The noun has one meaning:

Meaning #1: a worker whose job is to locate and fix sources of trouble (especially in mechanical devices)
  Synonym: troubleshooter