every time I try to open iMovie it says iMovie updating... but It won't open after an hour

Hi, shawnfromwoodland hills,

Try booting up in Safe Mode, as sometimes that cures little conflicts that hamper operations. Read this link for instructions:

Start up your Mac in safe mode - Apple Support

-- Rich

If safe mode doesn't cure it, and you are using an intel chip Mac rather than an M1 or M2 Mac, you can try resetting your Mac's System Management Controller. It's very easy -- a matter of booting up while holding down certain keys. As said, it is not available for the new M1 or M2 Macs. Here a link that describes the procedure:

Reset the SMC of your Mac - Apple Support

-- Rich

Another thing, you can let it update overnight and see if that solves it.

-- Rich