LINQ query check for unique object

Question

I have the following data in a List object;

List<FailedMachines> lstObjects:
lstObjects[0] - Desc: Mach1    Name:Drill  Id: 1
lstObjects[1] - Desc: Mach1    Name:Crane  Id: 1
lstObjects[2] - Desc: Mach3    Name:Grader Id: 3
lstObjects[3] - Desc: Mach2    Name:Mixer  Id: 2
lstObjects[4] - Desc: Mach2    Name:Paver  Id: 2
lstObjects[5] - Desc: Mach4    Name:Lifts  Id: 4
lstObjects[6] - Desc: Mach4    Name:Forks  Id: 4
lstObjects[7] - Desc: Mach5    Name:Forks  Id: 5

I would like to retrieve only the FailedMachines that are unique and NOT in a pair. Id = 3 & 5 in this case.

lstObjects[2] - Desc: Mach3    Name:Grader Id: 3
lstObjects[2] - Desc: Mach5    Name:Grader Id: 5 

Note that I'm using .Net Framework 4.8.