My wife's computer shows *only* other. This morning it was different. After she got a message saying her startup disk was full, I checked and found her 1TB drive on her 27" late 2012 El Capitan system had:
Other 521.03 GB
Apps 360.31 GB
Movies 52.03 GB
Photos 3452 GB
Audio 30.7 GB
Backups 8.4 GB
I noticed that iPhotos is 57.23 GB, & iTUnes is 258.11 GB. Odd, those don't match.
I deleted everything in her 42.7 GB movies folder, and turned off her computer.
Even though the "re-open" tab wasn't clicked, apps re-opened.
When I checked again, *everything* was "other". I ran diskutility with no change.
So I bought DaisyDisk, and it scanned for an hour. I decided to try it on my computer, and the scan took a second or so. I couldn't guess which apps were "other", so I dragged some to the bottom and deleted them. I hope I didn't delete anything my wife needs. I rebooted her computer. Not it shows 23.28 GB Apps & 719.98 GB other. The rest is shown as unused, so I opened Photos, and yes, there are photos there, even though DiskUtility doesn't know about them.
Any suggestions about what to do next?