One thing to remember with Parallelize[] and other parallel functions, is that Mathematica limits the number of cores it will use based on your license. So having more cores does not guarantee that they will be used.
Hany,
You need to post your code for anyone to help you. This question cannot be answered in the abstract. It is even better if you can post a small problem that exhibits the same behavior in a shorter amount of time.
Regards
I suggest using Task Manager or Activity Monitor (or the like) to see where your bottleneck is.
If you have concerns about the originality (authenticity, legality) of your Windows installation, you should contact Microsoft and have them check it for you, e.g. through a validation of license key on the phone or similar.
I used version 12.2 limits to 16 core. Is the originality of used windows may cause this problem?
