It seems like you're facing an issue with activating your trial version of 3ds Max using the serial number for the registered version. Here are some steps you can take to troubleshoot and resolve this problem: 1. Check Serial Number Compatibility: Ensure that the serial number you have is compatible with the version of 3ds Max you are trying to activate. Sometimes, different versions require specific serial numbers. 2. Run as Administrator: Try running 3ds Max as an administrator to ensure that it has the necessary permissions to write the serial number to the activation window. 3. Compatibility Mode: If you're using an older version of 3ds Max on a newer operating system, try running the software in compatibility mode...