My old iMac, which had an older version of iMovie, died recently. I got a new iMac which came with iMovie 10. I hadn't updated the old one since the reviews for iMovie 10 were not so favorable. I don't do a ton of video editing, btw. Anyway, welcome to iMovie 10. The first thing it does is convert all the old projects. It supposedly keeps the old versions for backwards compatibility. Apple says you can delete those old folders. Here is where I am confused. Some of my old videos/projects were stored on a 1TB external drive. My old iMovie Events folder shows 609.66 GB. The new iMovie Library created on that drive is 604.1 GB. Unless I am missing something, those two folders alone exceed my 1TB drive capacity, let alone the 234.42GB Lightroom Photo library that also resides on that same 1TB external drive, along with some other folders in the multi-GB range. I wanted to pull the old iMovie Events folder off that drive so I wasn't storing duplicate files on my main external drive, but I am wondering a) will removing it affect the new iMovie Library package that should contain all the old event files, and b) how much space is it really using since it is impossible to store of 1500GB of data on a 1TB drive as is currently reported.