Ghoul Problem

Ghoul Problem at (location) is a Minutemen radiant quest in Fallout 4. This quest can be started randomly when speaking to Preston Garvey, listening to Radio Freedom, or talking to a settler. If a settlement hasn't been unlocked yet, this quest may be started by speaking to a settler at that location, such as Blake Abernathy at Abernathy farm. This will unlock the settlement.

Failure to kill the targeted ghoul in a timely manner will result in the failure of the quest.

Detailed walkthrough

 * 1) Listen to the radio, talk with settlers or talk to Preston Garvey to get the quest.
 * 2) Speak to your contact in the settlement.
 * 3) Clear the ghouls from a random location. The Sole Survivor only needs to clear the targeted ghoul, usually a glowing one, to complete this objective
 * 4) Return to the contact in the settlement and inform them of your success.
 * 5) (Optional) If quest started with Preston or Radio Freedom, return to Preston Garvey. If one decides to skip this step, the experience points will not be earned right away but a couple days later, when the quest is supposed to expire.

Possible ghoul-infested locations

 * Bedford Station
 * Fiddler's Green Trailer Estates
 * Mass Pike Tunnel East
 * National Guard training yard
 * Poseidon Reservoir
 * Super-Duper Mart
 * Wicked Shipping Fleet Lockup
 * Suffolk County charter school

Bugs

 * If the player character is sent to kill the feral ghouls at Fiddler's Green, a quest marker may not appear. Killing all the feral ghouls in that location may not update the quest.  If this occurs, allowing time to pass until the quest fails may be the only way to complete it.