Looking for InDesign 2017 ver 12.0

Sounds more like you have a document corruption, there should be no difference in opening a 12 and a 12.1.

Maybe someone from Adobe might turn up on here and offer to have a look at your file (anyone around?).

ftistar  wrote Just updated my apps from 2017 to 2018 and now my old (2017) InDesign file that I was just working on wont open. I re-downloaded an old 2017 version of InDesign via the adobe cloud app, but that was version 12.1.0 and it seems like my file wont accept anything but 12.0, but I can't find that version of InDesign anywhere. Does anyone know how I can find version 12.0 or get my old files to work.

That should not be happening— normally CC2018 should open any fil created with earlier versions of ID. Can you provide More details about what happens when you try to open the file?