My Friend is stuck in Nigeria and has a paycheck for 65000 with him. He is unable to pay the taxes for it in the country and lives in the U.S. My question is can the check be voided if it is unsigned because he left the country?

No, first Nigeria has banks just like the US and you can deposit and cash a US funds check ( in fact they love them) at any major bank. Your friend may have to wait a week or so for that check to clear their banking system to have access to the funds.

But until a check has cleared the bank it was written on, it can always be voided and a new check issues. So the company that wrote that check can get with their bank and confirm the check has not cleared and payment on that check be stopped ( for a fee)

I would ask and I have to what "friend" since Nigeria is the major country for interent fraud, people from there contact people in the US and Europe every day with all sorts of scams to get people to send them money.

So anytime one hears the words, Nigeria and check and money scam just jumps to mind. So if this is a real friend, someone you know in person well and they went there for some business trip, great, but if not,?