Cannot update to 4.5

I haven't been able to install 4.5. I have 4.4.4 on MacOS. 4.5 DLs, but on install attempt, I get a dialog says: < Get Info, make sure “Locked” is deselected, and then check the Sharing & Permissions section. When you are sure the items are unlocked and not designated as Read Only or No Access, try again.>> But I have no idea what "items" are locked...