Mila Perry

One quick way to pinpoint it: with the jar off the base try spinning the blade hub by hand - if it feels gritty, wobbly, or has play, the jar bearing is shot. Also check that the blade assembly is fully tightened into the jar and that the plastic jar base isn’t hairline-cracked; a loose or cracked base lets the shaft wobble and grind. A burnt rubber smell or black dust around the drive coupler screams coupler wear, which is cheap to replace; otherwise, a new blade/jar assembly is often the economical fix. When testing, blip the motor for a second and avoid running the base empty for long.

Search stickied megathread; covered weekly. For what it's worth, taking a few minutes to practice this in a calm setting usually helps it stick.