I am updating a booklet created in 2015 with new information for 2016, and saving the file with a new name. Every time I attempt to flow in new copy, edit copy, or generally touch any element on the page, InDesign hangs up with the spinning ball for several seconds before I can proceed with my revision. This is cutting down on my productivity immensely. It happens with every document that I, (A) revise from an old version and (B) use items that I've copied/pasted from an different document, or dragged into the new file from another document. I'm saving locally, not to the cloud. I only have two computers on my network and the other computer is idle. Running InDesignCC 2015 on Yosemite 10.10.5. Any help out there?
Export the document as IDML. This will clean out extraneous code and minor corruption that can build up over the course of many revisions.