Running Illustrator CS5 on Mac OS 10.7
Reopening an Illustrator document expands all layers
For files containing a large amount of layers, this is very irritating.
Is this a general problem or just my version/me?
It's a consistent issue.
And there is nothing you can do about it. Users have been asking for a fix since..... well.. at least version 10, if not longer.
The simplest workaround is to place all your layers into a new top layer. Then, upon opening a file, you can Option/Alt click that top layer to collapse all internal sub-layers. This workaround has it's benefits and detriments. So it's not perfect.
I just wish they'd get around to fixing it.
The issue is with nested layers. If you build clean AI files, you use these a lot. The lack of a preference for this really stinks, but if you're organized with your top level layers it's not too bad.