Cannot upgrade past High Sierra
I have been trying to update my iMac from High Sierra, for the longest time. Finally came to the time when work is quiet so I have the time. I want to save the data on my machine, so dont really want to do a clean install. I have tried recovery mode but alas it is still stuck on the same screen, see attached screenshot. Has anyone else experienced this and is there a fix, many thanks in advance for your help
iMac Line (2012 and Later)