Known issue (several other posts already exist on this subject). I encountered this as well and solved it by putting the new update file 8.5.20 in the same folder as the 8.5.15 update file. I executed the 8.5.15 update file and then the 8.5.20 file. I can only guess that the new update expects the old files to be available. Good luck.
Hello - thanks for that.
So, in case others experience same problem, here’s what I did.
1 - Use REPAIR to fix the already installed 8.5
2 Run the latest patch.
Great. I wasn’t able to run repair so I had to rerun the 8.5.15 update. I hope Steinberg figures out what happened and avoids this issue in the next update. So many of us were affected.