I wish to apply for a masters in computer science in the United States as an international student. I have around 3 years of work experience in 2 companies. It is difficult for me to get any recommendation letters from my current employer. Would it reduce the strength of my application if I take it from a manager in my previous company and not the current company?
With a good recommendation from one employer and a good academic record you should be admitted to many masters degrees in computer science. The industrial experience is definitely a plus.
If you need funding you may have a problem. Many masters degrees aren't fully funded, even for strong applicants.