Autodesk’s licensing model is aggressive. The software constantly phones home or checks for local license servers. Any "cracked portable" version from a Taringa! thread from 2015 is almost certainly a time bomb—either a keylogger, a crypto miner, or a version that will crash the moment you try to generate a corridor surface.
While the "portable" tag sounds better, there are significant "gotchas" when downloading from sites like Taringa: Civil 3D Performance: Fix Slow or Poor Drawing Performance autocad civil 3d portable taringa better