Discord often struggles on startup because it's trying to load your entire message history and reconnect to all your servers at once, especially if you're in a lot of them. Try disabling hardware acceleration in Discord's settings (User Settings > Advanced > toggle it off), clearing the cache folder (usually in AppData/Local/Discord on Windows), or as a nuclear option, reinstalling it fresh. If that doesn't help, check whether Discord is set to launch on startup and disable it - then open it manually when you need it, since the forced startup load is often the culprit. You might also want to check Task Manager to see if Discord is competing with other programs during boot; if your drive is heavily loaded during startup, Discord gets starved for resources even though it's not a space issue.