Can I claim unemployment after I change my status to f1? I'm on an h1b status for the last 4 1/2 years and I'm in the process of changing it to student visa.

I believe that if you are on h1-b visa you are supposed to be employed during your stay. I don't believe you are allowed to claim unemployment (if by that you mean receive government help in any way shape or form for you're neither a resident nor a citizen). In case you manage to switch to F-1 status... assuming you'll be able to prove to an immigration agent you have enough ties to make you go back to your native country and you do not intend to reside in the US after the F-1 expires, you are in a totally new category that only allows you to work on campus for up to 20 hours per week... hope this helped.