Maybe there are many reasons to take longar time to take a Castep calculation. I am working with a Zeolite Structure. Especially, If the calculation protocols are ok, the size of the project is reasonable, and the single 4-core pc is in use, does it take longer than 3 weeks? How can I resolve the issue? Is there any suggestion? To resolve the problem, should I give importance in any part of my input files or software area, or my pc hardware? I want to get a short but tricky suggestion to get out of it. The job has no error message or any unwanted outputs. Only the job is running for larg time to finish the calculation. Advance thanks are here for you.