just "upgraded" to Mac OS High Sierra from Yosemite. Indesign CS4 now won't run. Loads partially; info panels greyed out and files won't load. Anyone know why or know of any solutions?
Moving to InDesign forum
As many others have found, InDesign CS4 will not successfully run on High Sierra (macOS 10.13.x). Your software is not supported either by Apple or Adobe on that operating system.
You'll need to use your back up copy of a previous macOS operating system and return to a previous version. Or you'll need to buy an inexpensive old Mac that has an older operating system in order to keep running CS4. It's simply too old and out-of-date.
Apple keep changing Mac OS. Compatibility is not their priority. If you upgrade your system it is vital to budget for all new apps. In a year or 2 all 32-bit apps like CS4 will stop forever.