ICloud – Photos app not uploading all photos

I just updated to the new Photos app on OS X and let it go through the process of importing my iPhoto library and uploading to iCloud. But it looks like about half of the library won't upload. It seemed to claim that it worked, but looking at iCloud.com shows that only about half of them are there. The iPhoto events were successfully converted to albums, but many of them are empty.

I went into the Photos settings and un-ckecked and re-checked the iCloud option, and saw this:

So I highlighted the whole library (command-A) and selected the "Consolidate" option. It took a while of course, but seemed to do the trick. It then went about re-uploading to iCloud.

After allowing that to finish, it appears that the problem persists. And performing the same steps in the settings results in the same message above.

The Photos Library in Finder is about the same size as the iPhoto Library, so I suspect it has all of the files. When I "Show Package Contents" all of the files appear to be there. And I definitely have enough space in iCloud.

Is there something else I can try?

Update

While "consolidating" again I was presented with this error:

Clicking "OK" brought up a file browser dialog. I selected the home directory folder as instructed, and then was shown an error saying that it couldn't find the original file (a .jpg) in that folder. Well, sure, the files are organized in sub-folders in the iPhoto library. Isn't that where it would look for them?