LTC4267

you have used 3rd party models in your simulation, namely: PS2911, BASS16 and TL431. I suggest you replace as many of these parts with similar parts found the in the LTspice libraries. It could be a problem with the model that is causing an allergic reaction with LTspice. Sometimes external models are overly complicated and LTspice therefore has lots of calculations to chew through. The LTspice models are simplified, but not to the sacrifice of accuracy, so they run a lot faster. Then... replace each component with the one you originally wanted, to work out which is the 'slow' component.

I did a quick and dirty replacement of the 3rd party components and my simulation runs quickly - attached4267_POE_Issue_worst-case_analysis_original_SB.asc

Hi Simon, 

Thanks for your reply. I will make those changes in my original design and try doing temperature sweep.