Hello, we recently had the need to change our PRTG Core Server. The problem was that we installed a trial version, because we could not stop our monitoring. Now we solve the problem, I need the server where is the Trial version has a registry key. When I insert the key, I get the invalid key message. What is mentoring? Not in any way I can stop my monitoring to reinstall another version. I thought by having licensed the product key, we would have problems.