Photos for Mac says "Unable to upload 222 items"
As you can see in attached screenshot, my Photos app works fine in uploading or downloading new files except that it says "Unable to upload 222 items". While that may be related to the format of files, I wonder whether I can know what items have not been uploaded. Its difficult to manually verify as i have almost 30k files in the iCloud. Are these unuploaded files stored in some file in root folder?
Thanks for answering
iMac, OS X Yosemite (10.10.5), null