Baking a simple rigid body sim fails repeatedly

I’m new to Blender, about 45 days in.

I have done this five times in a row, and it has failed each time.

I create a new scene in Blender 2.76b/2.77, and all it has is a pile of planks, sitting on a ground plane, with a ball. The ball hits the stack of planks, which falls down. Very straight-forward. I’ve done simpler versions and everything works fine. This particular scene, however, has 10,000 planks instead of a few hundred. It takes about 6 hours to calculate the sim.

After calc is done, I save the scene under a fresh name, and then bake the physics. After baking, I save the scene again, adding the term, “baked” to the scene title.

At this point, I add some cameras, plus empties for cam-parents and cam-targets, plus an HDR image for the world, and probably a light, also parented to an empty.

Then I attempt to make an OGL preview, and this is where I find that things are screwed up. The sim in NOT THE SAME. This happens in different ways each time: it may be that the ball has turned into a plank, or there might be a plank that just floats in the air (that was not there before and is NOT in the Outline), or maybe the ball jumps ahead several hundred frames on what was originally frame 6, etc., etc.

And I start over. Or I recalc the same sim, rebake it, and it gets screwed up again. I have done this five times this week, failing each time, which has taken almost an entire week of failure.

Is this typical? What might I be doing wrong? Any ideas?

2013 Mac Pro, OS X 10.10.5, 32 GB RAM

Thanks for any assistance.

What might I be doing wrong? Any ideas?
The main thing you are doing wrong is failing to supply your .blend file with your support thread. You must do this for ALL support questions or all anyone has to go on is a vague description and guesswork.

Enable ‘compress’ when you save your file, upload to tell us the download link

Thanks much for your kind reply, and for the link. I’ve moved on from those earlier scenes, and will keep this link for when trouble arises.