Freeing up space · Where your space went
What does the "couldn't account for" line in the space breakdown mean?
Short answer: It's the part of the change Storage Studio couldn't attribute to anything it measured. It's shown honestly as its own line instead of being spread across the other figures.
It's the part of the change Storage Studio genuinely couldn't attribute to anything it measured. Rather than scale the other figures so the total comes out neatly, it shows that remainder as its own line — so what you read is what it actually knows.
It shrinks as Storage Studio measures more: space held by automatic backups and temporary areas used to fall into it and are now named separately. A large unexplained figure is a good prompt to open What's Using Space and look at what changed.