Why an I having disc space problems?

I am cleaning up some old photos and I’m having a problem with Photoshop Elements 14. When I’m in organizer and I try to rotate a photo it says I don’t have enough disc space to do this task. If I bring that photo into Editor I am able to rotate without any problem. I’m using a Windows 10 machine and the photos are stored on a different machine using Windows 7. Both machines have plenty of disc space.

The directory where, about 16,000 family, pictures are stored is using 46.3 GB. That disc has 148 GB of used space and 759 GB of unused space. The Windows 10 machine has even more room at 931 GB.

Any suggestions as to What the problem might be?