After reading all the folks struggling with builds and bundles, I wanted to offer that the AutoBuilder asset (which I wrote, and recently put up on the store) may be a faster/better/easier solution for some of you. Apologies for sounding like an advertisement, but it's cheap and manages the asset bundle build and fully handles the caching process for you without you having to write any code to make it work. It does a lot more than just that, but I thought I'd mention it here, where people come looking for help. For those of you with a mostly working system that you've been struggling to get 100%, I know that pain. Wrote that, won't write it again. That's why I put up the asset--trying to make Unity easier to use for us all. Best of luck developers! JH