Photos library on my External Hard Disk not syncing with my iCloud Photos Library, how do I resolve this?

Hi rosav12,

Thank you for using Apple Support Communities. We understand your iCloud Photo library is not syncing and we'd like to help.

Just to confirm, you don't see the "Uploading" number increasing?

After you you moved the library over to the external drive did you open Photos from the external library as mentioned in Move your Photos library to save space on your Mac?

"Move Photos Library to the storage device

1. Quit Photos.
2. In the Finder, open the folder that contains Photos Library. By default, Photos Library is stored in the Pictures folder of your home folder. You can open your home folder by choosing Go > Home from the Finder menu bar.
3. Drag Photos Library to a location on your external storage device. Learn what to do if you get an error.
4. After the move is finished, double-click Photos Library in its new location to open it.
5. If you use iCloud Photos, designate this library as the System Photo Library.

If you want to delete the original Photos Library to save storage space on your Mac, you can drag it from its original location (the Pictures folder of your home folder) to the Trash. Then empty the Trash.

Always make sure that your storage device is turned on and available before opening Photos. If Photos can't find the device, it stops using the Photos library stored there"

If not, it might be opening from the internal drive still.

Let us know.

Cheers!