LyX v2.5.2 PDF crash when figures are missing?

[Bernt Lie]

LyX v2.5.2... corrupted PDF file with undefined figures -- I don't think this used to crash in the past?

I am copying a LyX file from one location to another. When I open the file in the new directory, figures are flagged as "not found", even though I have placed a copy of the figure directory in the same location relative to the LyX document. 

When I try to preview this document as PDF, I am told that the produced PDF file is corrupted, and nothing shows up in the pdf previewer (happens both on Windows with PDFgear, and on Mac with the previewer).
--
A perhaps related question... I have now set up LyX so that it (i) checks the OS, (ii) based on outcome of OS specifies path to my OneDrive location on my laptops. This works fine for templates, etc. But not for figures and child documents, I suspect?