As is sacred tradition with all Bethesda games, Skyrim Special Edition launched with a whole array of bugs and glitches. It was prone to crashing, the FPS randomly dipped into single digits for seemingly no reason at all, water would occasionally stop being liquid and turn into a flat surface, and things like that.
To Bethesda's credit, they quickly reacted by putting out Update 1.1. - which actually ended up making things even worse by introducing previously unseen varieties of crashes and audio problems! Thankfully, it appears that the second time's the charm as the recently posted Update 1.2 has not only managed to remove most of the crashes, but also most of the problems introduced with the previous update! Here are the brief, but hopefully effective patch notes:
• General stability and performance improvements
• Fixed issue related to using alt-tab while playing the game (PC)
• Fixed issue with water flow not rendering properly
• Fixed crash related to changing from werewolf back to human form
• Fixed crash related to reloading after changing Load Order of mods
• General bug fixing and improvements with browsing Mods
For me personally this update has managed to correct most of the problems, but a quick glance over at the Steam forums shows that not all crashes have been fixed just yet. If you're among those still affected, worry not as Bethesda is already working on the next update, but unfortunately its probably going to take a little while to come out. Until it finally arrives I would recommend playing with as few mods as possible, just to make sure there's as little "outsider" interference as possible.