Keep useful records
SpacePeek previews existing folders and archives. Keep original archives and important paths; moving to NullDisk does not transfer Quick Look extension features.
What you can keep from SpacePeek
SpacePeek previews existing folders and archives. Keep original archives and important paths; moving to NullDisk does not transfer Quick Look extension features.
Saved scans describe files at a point in time. They do not contain the original file contents, and they do not replace a backup.
Switch in four steps
Match the location and scope
Scan the same folder or volume in NullDisk. Match permissions, exclusions, and measurement mode where possible. A current scan will differ from a historical one if files or access changed.
Review the files, not just the total
Confirm full paths and previews. Logical size, allocated size, cloud object size, hard links, APFS shared blocks, and snapshots can explain differences between tools.
Choose an explicit cleanup action
In the Mac app, review collector items and the selected source before choosing Trash, permanent removal, or backup before deletion. Keep historical exports separately. Trash and snapshots can delay recovery of space.
Save a structured NullDisk report
Install the standalone CLI, then scan a location you control. The following commands inspect data and write reports; they do not remove files.
nulldisk scan ~/Downloads --json > disk-report.json
nulldisk dev ~/src --json > development-report.jsonReports may contain private paths. Review them before sharing and check the command’s exit status for incomplete results.
Common questions
Can I export a scan from SpacePeek?
SpacePeek previews existing folders and archives. Keep original archives and important paths; moving to NullDisk does not transfer Quick Look extension features.
Can NullDisk import another analyzer’s scan or cleanup queue?
No direct import is documented. Scan the same filesystem again, preserve old reports as historical evidence, and rebuild only selections you have verified against the current files.
Can I export from NullDisk?
The separate nulldisk CLI produces JSON and NDJSON disk/development reports. These reports describe the measured scope; they are not backups or a GUI session import format.