We are a solar installation company that uses Sketchup Pro and Layout to create installation and permit drawings. Over the last few months, we have had more and more Layout files that have dropped embedded images. These are not imported SketchUp Models - they are things like logos and jpgs that we have had in our drawing templates for years without problems.
Often the drawing will be fine, then the next time we open it some or all of our embedded images have a grey box with a red X through it. All four designers use Sketchup 2018 running on PCs. We store our Sketchup files and Layout drawing in Dropbox folders. If you go into Document Setup \ References, the File Names are gone from the missing images. We have used the same work process for many years and have not changed anything, apart from upgrading to Sketchup 2018.
We have used Sketchup since 2007 with no major issues and love the software, however, we will be forced to use something else if this problem can’t be solved.