Hi I'm using Filemaker Pro Advanced 16, on OS X El Capitan (10.11.16).
Filemaker wasn't responding, so I forced the application to quit. When I reopened the file, all of the records were still in the file but on the layout that was open all of the contents were erased (every object, field, button, etc was all erased). I've relaunched both my computer and the solution, and the layout contents are still absent.
Luckily I have a backup, so this is not catastrophic, but am confused to how/why this happened and how to prevent future loss.