How do I "unhang" Photos iCloud library merge/uploadinfg
I have 4 Photos libraries on my iMac. I am trying to create a single Photos iCloud library. I think I know the basic approach, i.e. make 1 of the 4 libraries the system library, turn on iCloud Photos and let it upload into iCloud Photos. After it's uploaded, do the same thing with the next library on my iMac, etc.
So, my first library uploaded OK. The second library uploaded about 4,000 pictures, but is hanging saying"uploading 22 items". It has been hanging at 22 for a few hours.
What are the options for moving on to uploading my 3rd library and forgetting the 22 items? Maybe one of them or all of them are corrupt or a format that Photos can't handle for some reason. Or, trying to get those last 22 uploaded?
Any ideas most welcome.
iMac 21.5", macOS 10.15