Troubleshooting & messages · Permissions and Full Disk Access
Why does a folder's size say it's only a minimum?
Short answer: Some of the folder couldn't be read, so the figure is what could be counted — the real size is at least that. Full Disk Access usually lets Storage Studio count the rest.
Part of the folder couldn't be read — usually because macOS protects it, or an app has it locked — so Storage Studio shows the size it could count and labels it a minimum. The real size is at least that, possibly more.
Granting Full Disk Access in System Settings → Privacy & Security usually lets it count everything. Some system areas stay unreadable to every app by design.