After good results running High Sierra Public Beta 2 on my MacBook Air (mid 2012) and office iMac (late 2013), I tried to install it on my new iMac 5K 2017 (3.8GHz i5/32GB RAM/1TB SSD). I followed the exact same procedure as on other Macs: Enroll the iMac Download and install macOS Public Beta Access Utility Download the beta installer When I ran the installer, it gave this message: Installation of macOS could not continue. Installation requires downloading important content. That content can't be downloaded at this time. Try again later. I tried many times and the results remain the same. Is it because my iMac is too new and Apple haven't added support to it in the beta? Has anyone managed to install High Sierra Public Beta 2 on new iMac? If yes, please share your experience here.