I have this scene and I have imported a tree model using the append function. I alt-d a bunch of trees onto the scene, scale them around a bit to fake some depth. This takes a bit to do. When I’ve finished that (finally) I save it. Then I open it up again, and all my changes are gone!!! It’s just the trees. If I do something else, like delete an object that’s already there, they stay gone!!!
I’ve further investigated it. The objects still appear in the outliner, they just don’t appear in the scene. The weird thing: it won’t let me deselect them in the outliner!
EDDDDDDDIIIIITTTT: You’ve gotta be kidding me! It decided to put an IPO on the objects!!! So they were there all along, just stacked all on top of each other!!! Man that pisses me off!
I doubt Blender decided to put an IPO on them. Either the original already has an IPO on it or you added an IPO somehow - probably because auto-key was on or you accidentally hit the I-Key without realising you were keying the tree.
I just had the same thing with an item I added to a scene. In my case, the item was created two years ago and I was dumbfounded when everything jumped to a single location after I’d spent time re-arranging multiple copies of it. But the fact is, I had keyed the original when I made it - and ordinarily I’d want the IPO to come with it.
Sure it’s frustrating when you lose work, but if you want a future with Blender you’ve got to stop getting pissed off at things that go exactly how you assume they should go. It’s just not going to happen - no matter how much you shout and swear.
So, take a few deep breaths, delete the IPO channels, get re-arranging and learn from the experience. That’s the best you can hope for.