If lite.computer cannot read a folder, Showspace health explains what was skipped and why.
Start with the health check. It lists folders the app could not access, folders more than twenty levels deep, and pages beyond the 2,000-page limit. It also tells you if the scan stopped before finishing.
Check macOS permissions first. Open System Settings › Privacy & Security › Files and Folders and allow lite.computer to access the location. Then open the folder again in the app.
USB sticks and drives formatted for other systems work. macOS writes its own sidecar files onto them, and the app skips those, so your page count is the real one.
Still stuck? Write to support@lite.computer.