I had this problem earlier.   There are three G2 figures in a scene:  Sydney, Jessi and Simon.   It may be significant that they went into the scene in that order.   With the three of them and their various odds and ends, Poser was taking a fair amount of memory, but the saved file wasn't notably big on the hard drive.

  When I tried to render the scene all in one go, Poser gave up trying to render, but continued running, so I hid part of the scene and rendered the rest.   After that, Poser put out a message about being unable to load a texture, so I closed it and re-started it.   When I tried to open the scene, I was prompted to locate a file called 878628384.obj.   Since it was nowhere in the Poser folder, I had to take the option to give up the search.  

  The scene came up with Sydney and Jessi all present and correct, along with Simon's clothing - but no Simon.   I closed it without saving and tried opening a slightly earlier saved version.   This asked for the same mysterious .obj (or one with a similar nine-digit number, anyway), so I pointed it at the Simon geometry file.   Now everyone was in the scene, but Simon was unmorphed.

  I had a look at one of the saved Poser files and there were two references to 878628384.obj:

morphBinaryFile D:Program Filese frontierPoser 7RuntimelibrariesCharacterPoser 7SimonG2SimonG2.pmd
figureResFile C:DOCUME~1ABCDEF~1.ATHLOCALS~1TempPoser 7PoserUndoCache878628384.obj
actor BODY:10

  I have pretty much re-created the scene as it was, so I am not greatly bothered about repairing the old file, but I'd be interested to know what is causing the problem and how I can be confident of avoiding it, if anyone has any ideas, please.

Okay, we've gone over this a lot.  Do you have the P7 SR1 installed?  

I see you're using External Binary Morphs ... this has created a lot of corrupt files before the SR1.  Try disabling that before you save your scene.  I never use that option and I've never lost a scene, even with 3 V4's and an Apollo Max in it.

That's certainly an odd occurence.

If you did want to repair the file, you should be able to do so by replacing the path in the two figureResFile lines with the correct path to the figure's OBJ file (these lines always specify OBJ as the extension even if the file is really an OBZ).

If this keeps happening, then you should send in a bug report.

Actually, I don't know if SR1 is installed.   I definitely downloaded it (which probably means I applied it), but I don't recall if I ever put it on    "About Poser" gives 7.0.0.63 - Poser 7 SR1, or Poser 7 base?.   I am still trying to render this scene, so I am not going to try re-installing the service release until that is finished, because I may lose the whole thing again, if I save it and get another damaged file.   I shall certainly follow your advice, though.

I thought that the external binary morphs problem was a V4 speciality and I don't use V4 often.   I have a funny feeling that I have always had external binary morphs set like this, but, if I did change it, I don't recall the reason.   (I was out of the country for most of March and nowhere near any 3D software, which is why some things I may or may not have done in February are a bit sketchy, to say the least.)  

Once I have edited the Poser file, how do I get Poser to recognise it as such?   I did do a modification of that kind, but I have only the basic Windows editors.   Do I need something else?  I tried "Open with...", but that doesn't find Poser 7, even when I specifically identify the Poser.exe for Poser 7.   

Many thanks, Victoria_Lee and nruddock, for your suggestions. 

Quote - Once I have edited the Poser file, how do I get Poser to recognise it as such?   I did do a modification of that kind, but I have only the basic Windows editors.

If you save without compression, then most of Poser's files are plain text.
For one that aren't to big, then WordPad is usable.
Just start WordPad, and then use File | Open to select the file (you'll need to switch the filter to "All Documents (.)" to see files with Poser's extensions).
When you save (work on a copy!), you may get an extra ".TXT" extension added (which needs to be removed).