Hi guys, currently i bought an Mac Mini mid-2011 to set it up as server. The Mini had installed Lion 10.7.5. I made an upgrade to Sierra and it worked. Then I bought and installed macOS Server. Trying to setup macOS Server gave me always an error "Unable to run macOS Server 5.2 with Sierra on this volume". After this error I tried to reinstall Sierra completely. Therefore i started with CMD+R and erased the disk. Trying to install then Sierra again gave me always an error after about 15%. The installer aborts and message me its not able to install the system. Also the internet recovery via CMD+Option+R, starting with OPTION and choosing the recovery partion and installing via USB-Bootable installer (Diskmaker X) doesn't work. I tried to download Lion, Yosemite, El Capitan and other versions on my macbook pro with sierra, but its not possible because app store says i cant use this version of OSx. Are there any options left to bring any OSx on the mini back? I have an Snow Leopard disk, but the mini has no drive. I also have an firewire cable. Thx guys for help..