Last Resort: DUPLICATE the project and try working from the fresh copy. re-add any missing assets to the project bin.double check that any Adobe Fonts you may be using are activated and connected.Then try editing and/or exporting, and you should be good to go. For example it takes long time to load youtube video, then it starts playing, but if i skip song or whatever is on video to forward, then it freezes and stops playing.
Open your project, and BE SURE TO WAIT for it to FULLY SYNC. I have problem that my media on windows 10 is quite often freezing. Hold CTRL + SHIFT buttons while starting Adobe Rush - this will tell Rush you want a "fresh start" without losing your projects it will open the Starter Tutorial like you were starting for the first time - simply close the tutorial, and your projects will be available. Sign back into your Creative Cloud Desktop App. RESTART YOUR COMPUTER, and make sure you don't have any memory-intensive ("RAM-hogging") apps running while you're starting up (I never run Photoshop, Illustrator, or Microsoft Office apps while working on videos). Close out your project, and sign out of Rush and Creative Cloud.This usually does the trick for me if a video stalls out: