If you have a check from someone who has passed away, it can legally be cashed, and you should be able to receive the money. However, there may be financial problems with the estate that could prevent you from getting the funds. If this is the case, you can try to cash the check, but there is no firm guarantee the bank will pay on it.
Just because the person who wrote the check has died does not mean you will not be able to receive your money. As long as there is still a bank account with money in it, there are funds for you to access. So take the check to your bank to cash it as long as it's a valid check signed by the decedent and made payable to you.
Individual banks may take different actions when account holders die. If a relative informs the bank the account holder has died, the bank may limit the funds it will pay on checks written before or on the day of death, and those presented within 10 days after the date of death. For example, if the account holder died on March 1, the bank might pay checks written on or before March 1, up to March 10 and then stop paying funds on March 11.
If the person who died has a lot of debt, you may be waiting in line for those funds. Interested parties or heirs could contact the bank and tell them not to pay out checks while they sort through the finances. Heirs are not automatically obligated to pay the debts of dead people; so if you try to cash the check and are not able to because of financial problems with the estate, you may need to legally file a claim to get paid.
Chances are, if you know the person is dead, you know some friends or relatives, so this could be a dicey matter. Try to cash the check once you hear of the death; if you're within the 10-day time frame, you should have no problem, so long as a relative hasn't asked the bank to stop payments. If there's a problem at the bank, consider talking to the executor of the estate, or a friend or relative about the money matters. If it's a small check and you cannot get paid, decide whether you want to pursue legal action or let the money go.