If the Riot Client stays on Update, Preparing Download, Installing, or a progress bar that never moves, the launcher is usually failing before the patch can finish its normal file check. A Riot update can stall because the launcher is still stuck in memory, cannot repair or write files, cannot reach the patch servers cleanly, or is waiting on Vanguard for a supported game. The loop can be misleading because the client may still open, sign in, and show your games normally.