files in iCloud can't be copied

Hello Li_Ali,

The error could be caused by the actual file type, but we'd like to resolve the issue by completing the steps listed here: If you can’t move or copy an item on Mac - Apple Support that can also be found below.

1. On your Mac, select the item, then choose File > Get Info, or press Command-I.

2. Click the arrow  next to Sharing & Permissions to expand the section.

3. Click the pop-up menu next to your user name to see the permissions settings.

If you’re not logged in as an administrator, you may need to click the lock  to unlock it, then enter an administrator name and password (or use Touch ID or your Apple Watch).

4. Change the permissions to either Read & Write or “Read only.” 

If you need to, also change the permissions for the location where you want to put the item.

Best regards