I have attempted to update to the new OS from Yosemite since last Friday. It has ben stuck in "paused" or "waiting" ever since then. I have checked a number of posts online, and tried a variety of things to get it re-started. The latest was to go the app store, click on unfinished downloads, and restart. I have done that, and a window comes up stating all downloads are complete. However, both Launchpad and the app store show only 400mb downloaded out of 6.5g for this update. How do I cancel this process, restart the process, delete the download, etc? I am using a 2011 21.5" iMac with 4g of ram.