Take control of disk space on a Windows PC

RP-003 concerns storage management on a computer used by a person: understand what consumes space, choose a suitable action and avoid data loss. It is distinct from RCS-RP-002, which studies hardware-dependent compression algorithm performance.

The experiment used an 8 MiB repetitive log, an 8 MiB pseudo-random binary file, and a ZIP archive containing that binary file. The log is an intentionally favourable case for compression; the other two represent low-redundancy or already-compressed data.

For the synthetic log, ZIP greatly reduced size and NTFS Compression reduced stored space to one eighth. For the random binary file and its archive, ZIP added a small amount of overhead and NTFS Compression did not reduce stored space. Recompressing is therefore not a universal strategy.

These figures describe three constructed patterns and one run on one PC. They are not average savings by file category and include no speed, latency, CPU or battery measurements. Keep a verified backup before deleting anything.

Work in small steps and check free space after each one:

• Start with Settings → System → Storage and review Windows cleanup recommendations before confirming anything.
• Use a disk-usage analyser such as WizTree to locate large items. A large file is not automatically unnecessary or safe to delete.
• Uninstall unused applications through Windows Settings instead of manually deleting their folders.
• Move or archive cold data only after verifying a copy and a backup. Moving files within the same volume does not free space.
• Reserve compression for genuinely redundant data and test a small sample. Do not expect large gains from JPEG, video, compressed audio or archives.
• Review Storage Sense rules for the Recycle Bin, Downloads and cloud files; automated deletion can remove items the user meant to keep.
• Cloud files marked online-only depend on connectivity and may not be available offline. Synchronisation is not an independent backup.
• Prevent recurrence by choosing where new large files are saved and periodically repeating a targeted review.

WizTree is a disk-usage analyser, not an automatic cleaner. Its views can help locate large files and folders. “Size” is logical file size; “Allocated” is the space allocated on disk and can differ due to compression and allocation units. Some NTFS metadata is not counted as files, so totals can differ from Windows Storage settings.

For an ordinary inspection, start without administrator privileges. The vendor says its high-speed NTFS scan requires elevation; only use that mode when needed and when you trust the application. Never delete a system item just because it looks large in a treemap.

The tables are measurements produced by the described protocol. Advice about Storage Sense, OneDrive, NTFS and WizTree comes from the external sources below; it was not tested in this experiment.

• Three synthetic files, one run per case and one NTFS volume: representativeness is limited.
• No personal files scanned; no tool installed; no existing data modified or deleted.
• No WizTree product benchmark, no 7-Zip test and no application-performance measurement.
• Windows labels and behaviour may vary by version, language and settings.