Were you able to roll the 12.0.4 version back or did you have uninstall & reinstall FM completely? Did you reboot between operations? Have you tried using the direct upgrade path - Adobe - FrameMaker : For Windows
I had to uninstall/reinstall the whole TCS package which got me back to 12.0.2. Then I updated 12.0.3, which works with SharePoint 2013. It’s unclear if 12.0.4 works with SharePoint 2013; Adobe support (who walked me through this) says it should (it’s supposed to include everything from earlier updates, which is what I was expecting), but I am out of time to experiment.
For anyone finding this thread at a future date...
Whenever I have trouble uninstalling Adobe software, I use the CC Cleaner tool. As with many dev tools, it has the power to do more than you wish, but it is quick, and has yet to let me down.
Don't rush through the options, and you'll be ok.