Can't play my own video!

OK - that suggests your macbook storage is full, or close to full.

What do you see when you click "manage storage"?

Setting optimise mac storage should remove full size images and videos from your mac and only store them in iCloud. BUT it might not be able to start this process if there is insufficient space.

Before we do anything else - I have to check. Are ALL your images and videos stored in iCloud? Do you also use an iphone to take pictures/videos? Can you check at www.icloud.com

(Log in with your apple id and click the photos icon to check everything is there)

Hi

Have you enabled "optimise mac storage" in iCloud settings? This error normally occurs because the full size video is not on your mac. It should download when needed - but

• Videos are large so it may take some minutes depending on your internet speed
• This may not work if the iCloud library is not fully synced. What does the status say at the bottom of the all photos view?

(Here is mine - "updated just now")