macOS Sierra and newer include an option that will automatically optimize storage on your local drive by removing data and storing it in iCloud. When this happens, Mylio loses access to the original file, resulting in Mylio not seeing the photo is there and being removed from Mylio. The removal of this file from Mylio is then synced to your protected devices and other devices on your account. This results in a situation where Mylio does not display images that you may expect to see, or you are able to see in Finder.
At this time, it is recommended that you do not use Apple’s Storage Optimization features in conjunction with Mylio as it can cause apparent data loss (though not actual data loss as your photos are in iCloud). We are investigating resolutions for this in future versions.
To turn this feature off:
- Open the Apple menu on your computer running macOS Sierra or newer.
- Navigate to System Preferences, then iCloud.
- Select Options next to iCloud Drive.
- Disable Optimize Mac Storage at the bottom.