I was looking to use my Boot Camp VM, and saw the support documents stating that with High Sierra, only Parallels 13 can launch Boot Camp VM's. Frustrating, but I bought the upgrade to get it working. However, the VM is refusing to boot, stating that the hard drive referenced cannot be used, exactly as others have posted happens with Parallels 12 under High Sierra. Support documentation claims that the only supported path for doing this is to have purchased this upgrade - am I missing some conversion step, or am I just SOL? I sent technical information in report ID 214795287 if that helps anyone at Parallels see what's going on.