Duplicate comparison can require reading file contents, so duration depends on count and storage speed rather than total size alone.
Scan one narrow folder, avoid selecting a parent and its child, and raise the minimum-size threshold. Connect external drives directly and avoid unstable network volumes.
Finish cloud downloads first. Close other disk-heavy apps and connect power.
If progress stops at the same location, scan its subfolders separately to isolate an inaccessible or damaged file. Preserve the disk and run appropriate disk diagnostics before retrying.