Thanks jonnybode/ironsoul - I just did another check of my 'LibraryPrefs.xml' file, and there's no special characters in any of the pathnames, so I was going to say "No, it's not that."...

But then I took another look...

    <ContentFolder folder="G:Poser$DAZRuntimeLibraries"  index="4" >
        <Library libraryType="2"  curLibraryFolder="character" />
        <Library libraryType="8"  curLibraryFolder="props" />
        <Library libraryType="9"  curLibraryFolder="materials" />
        <Library libraryType="1"  curLibraryFolder="pose!FolkV4V4 StancesV4 Brianas Stances" />
        <Library libraryType="7"  curLibraryFolder="hairV3V3 Erin Hair" />
        <Library libraryType="3"  curLibraryFolder="light" />
    

Like I said, no special characters there, but if any of my library subfolders have a special character in the name (and Windows allows & and ' ) and I happen to close Poser with that folder selected? That would explain why it sometimes happens, sometimes doesn't, and isn't repeatable.

I guess it's time to go hunting naughty little ampersands and apostrophes :)

---

The 3Dcheapskate* occasionally posts sensible stuff. Usually by accident.
And it usually uses Poser 11, with units set to inches. Except when it's using Poser 6 or PP2014, or when its units are set to PNU.

*also available in ShareCG, DAZ, and HiveWire3D flavours (the DeviantArt and CGBytes flavour have been discontinued).