Difference between computer science MS and MCS

Many Master's degrees exist that could reasonably be considered "computer science" degrees, and the distinctions between them differ from one university to another. Thus, you should probably ask someone familiar with the programs that you're considering about the particulars for that scenario.

The best general answer to your question, if there is a general answer to it, is that many of the degrees named simply "Master of Science" require writing a thesis. For example, compare North Carolina State's Master of Science program with their Master of Computer Science program. Often the thesis degree is awarded to PhD students who have completed their qualifying exam and coursework, but this also varies from one university to another.

Since writing a thesis is an important distinction for Master's degrees, you may wonder what a thesis is and how it might be viewed by potential employers. A thesis is a document produced as the result of academic research. While you will learn more about analyzing academic research, formal writing, and how academia works in your field of study, you will not typically learn more skills that are directly applicable to the profession. For this reason, you can think of the thesis master's as an "academic" degree and the non-thesis master's as a terminal "professional" degree, but that's also a bit of a simplification.

If you're looking at degrees that start with "Master of Science in" and end with something like "Computer Science," "Computer Networking," or "Software Engineering," then you probably won't have to write a thesis. These Master of Science names differentiate a degree in science, engineering, or medicine from a degree in English, history, or philosophy, which are Master of Arts degrees. Often, these are both shortened to just "Master's" degrees. So instead of a Master of Arts in History, you might simply say that you have a Master's in History. For example, NCSU has a Master of Science in Computer Networking, which is regularly shortened to Master's in Computer Networking.

There is unfortunately no one general answer that applies across the board.

For specific degree requirements (so you know what you're going to be learning), you should look up the individual programs. The only specifically non-professional masters degrees are ones you may get en-route to a Ph.D. (often called an M.A. or an M.Phil.), but even there, there are differences in naming conventions. Moreover, terminal masters degrees often have the same names but have a "thesis option" or "course option" depending on your career goals.

Luckily, where you go, how you do, and what you learn will matter a lot more than the name of your degree. At least in the US, nobody will care whether you have a M.S. or M.C.S. or whatever else -- they'll just think of you as having a "master's."

In some countries MCS (2 years) is offered as a 16-years graduation degree, which is equivalent to BS(CS). It is offered specifically for those who have earned a 14-years bachelor degree or sometimes for people coming from other backgrounds, to provide them a fair enough base in computer science.

A computer science MS or MSCS are both similar terms (2 years long), which is an 18-years graduation degree.

Coming to your question:

Is is true that MCS is more "professional" in the sense that it doesn't prepare students for a PhD but it is for who wants to directly work after graduating? Do they both last 2 years?

The answer is: Yes, MCS is like any other professional degree out there. In addition, after having an MCS degree, an MS degree (2 years) is still pursued to get prepared for a PhD degree.

MS degree mostly has a thesis, while MCS, if it has the one that is definitely, we can say the lighter one, since the candidate has not been trained at this level to produce a thesis.

Does the thesis help you getting hired?

This simple most answer is: "It totally depends upon the employer and her demands for a specific position offered".

As I said:"MS degree mostly has a thesis". Well I know people and the universities were they have MS degrees (18 years) but without a thesis. So how do they do this? Mostly they compensate the research credits with additional course work.

I also know places/individuals (internationally) where people with 'MS degrees without a thesis' have also been haired for an explicit research positions (e.g., Research associates, PhD students with RA ships, etc.) in academic institutes for academic research. Where, mostly thesis is a requirement OR in other words a thesis is inevitable to provide a candidate with the required skill set for such positions.

Finally, while considering the above description about the acronyms valid, I would say that a thesis with an MCS degree has an importance similar to to any other professional degree with thesis (i.e., the case when a thesis is also prepared at end of a professional degree in order to fulfill the requirements).

N.B. Some universities also name MCS to a computer science MS degree.