I was trying to run a Path Integral molecular dynamic with the Material Studio build-in CASTEP. It works OK after adding to the simulation file keywords like:

md_use_pathint : true
md_num_beads : 16
md_pathint_staging : true
num_farms : 1

It is required to check "keep files on the server" otherwise the alternative beads .md files are deleted. I had encoded in C# a routine processing the .md files so analysis+movie can be done e.g. in VMD software (Materials Studio Does not support PIMD analysis directly).

What does not work totally is CASTEP multi processing based on the num_farms keyword. If I set num_farms = 16 (as suggested for optimal PIMD run performance) on the 32 core machine, Material Studio CASTEP crash, generation multiple .castep files and reporting issues with FORT11 file sharing. I am afraid the Windows port of CASTEP is incorrectly done in relation to the num_farms keyword. Any solution ? 

Btw. I have an identical issue with my CASTEP binary build based on cygwin64 enviroment ...