Why won't App Store download High Sierra
When I try and download High Sierra from App Store, rather than the icon saying "Download" it says "Open", but the installer is corrupt it says when I try the "Open". I tried to rename the corrupt installer app package and then tried again in App Store and it tries and open the same file (so the rename had no effect which seems rather odd unless it keeps track of the installer by inode number or ???). This is a result of clicking the "Get macOS High Sierra" link that is located on the web page at https://support.apple.com/en-us/HT208969
So any ideas on how to "reset" App Store so that it can download another High Sierra installer app or really how the App Store remembers this information about previous apps that is has downloaded previously?
Thanks...
Mac Pro, macOS 10.13