Ferry operator Condor said a mezzanine ramp was fixed and the vessel departed at about 10:10 BST.
Repairs to an electrical fault on the Condor Liberation were completed earlier this week.
Last month it was put out of action on its second day in service after it struck the quayside at St Peter Port.
Problems loading vehicles on to a new £50m ferry meant the Poole to Guernsey service on Saturday morning was delayed by 40 minutes.