You are essentially replacing the SC3.exe in your installation folder with a modified version that skips the disc-check trigger.
Uses ~650 MB of disk space and requires the virtual drive to be mounted each time. But it is 100% malware-free and works with every version. simcity 3000 no cd patch verified
Right-click your SC3.exe , go to Properties > Compatibility , and set it to Windows XP (Service Pack 3) . You are essentially replacing the SC3