Scan My Folders for Malware: Quick Checks You Can Run Today

Scan My Folders on Windows, Mac, and Linux — A Cross-Platform GuideKeeping your files organized, secure, and free of duplicates is essential for productivity and system health. This guide covers how to scan your folders on Windows, macOS, and Linux for duplicates, malware, large files, and general clutter. It includes built-in tools, trusted third-party utilities, step-by-step instructions, and tips for maintaining a clean file system across platforms.

---

Why scan your folders?

Scanning folders helps you:

• Reduce wasted disk space by removing duplicates and large unused files.
• Improve performance by decluttering indexes and backups.
• Protect against malware and accidental exposure of sensitive files.
• Make backups faster and more reliable.

---

Windows

Built-in tools

• File Explorer: Use it to sort by Size, Date modified, or Type to find large or old files.
  • Open File Explorer, navigate to a folder, click the Size or Date modified column to sort.
• Storage settings:
  • Settings → System → Storage → Click drive → Use “Temporary files” and “Large & unused files”.
• Windows Defender / Microsoft Defender:
  • Start → Settings → Privacy & security → Windows Security → Virus & threat protection → Quick or Full scan.

Duplicate and large-file scanning (third-party)

• Duplicate Cleaner or CCleaner — effective GUI tools for finding duplicate files and cleaning temporary files.
• WinDirStat — visualizes disk usage so you can spot large folders and files quickly.

Example steps with WinDirStat:

1. Install and run WinDirStat.
2. Choose drives or folders to scan.
3. Use the treemap and list to find large files and navigate to them in Explorer to review or delete.

Example steps with Duplicate Cleaner:

1. Install Duplicate Cleaner.
2. Select folders to scan and choose match criteria (name, size, content).
3. Review matches, then move duplicates to Recycle Bin or a separate folder.

Malware scanning

• Run Windows Defender Full scan for thorough checks.
• For extra assurance, use a reputable on-demand scanner like Malwarebytes:
  1. Install Malwarebytes.
  2. Run a Threat Scan or Custom Scan targeting specific folders.

---

macOS

Built-in tools

• Finder: Use the Search feature with filters (Kind, Date, Size) to locate large or old files.
  • Press Command-F in Finder, then add search criteria (e.g., File Size > 100 MB).
• Storage Management:
  • Apple Menu → About This Mac → Storage → Manage. Use Recommendations, Documents, and Reduce Clutter.
• XProtect & Malware Removal Tool: Built-in macOS protections run in the background; use a third-party scanner for deeper checks.

Duplicate and large-file scanning (third-party)

• DaisyDisk or GrandPerspective — visualize disk usage to quickly find big items.
• Gemini 2 — easy duplicate finder with a polished UI.

Example steps with Finder for large files:

1. Command-F in Finder.
2. Choose “This Mac” and set Kind to “Other…” → File Size.
3. Set filter to greater than 100 MB and review results.

Example steps with Gemini 2:

1. Install Gemini 2.
2. Add folders (e.g., Pictures, Music) and scan.
3. Review duplicates and let Gemini suggest which files to keep.

Malware scanning

• Although macOS has strong built-in protections, use Malwarebytes for Mac for extra checks:
  1. Install Malwarebytes.
  2. Run a Scan (Threat or Custom) against selected folders.

---

Linux

Linux distributions vary, but the following tools and commands are widely available.

Built-in commands and utilities

• du — disk usage:
  • Example: du -sh * | sort -h lists folder sizes in the current directory sorted smallest to largest.
• find — locate files by size, name, or date:
  • Example: find /path/to/scan -type f -size +100M -exec ls -lh {} ; finds files larger than 100 MB.
• locate / updatedb — fast name-based search (needs updatedb run periodically).

Duplicate and large-file scanning (CLI and GUI)

• fdupes — command-line duplicate finder:
  • Install: sudo apt install fdupes (Debian/Ubuntu)
  • Run: fdupes -r /path/to/scan for a recursive scan.
  • Use -d to prompt for deletion (use with caution).
• rmlint — faster duplicate and lint finder:
  • Install and run: rmlint /path/to/scan then review results; it can generate scripts to safely remove duplicates.
• Baobab (Disk Usage Analyzer) — GUI visualizer available in GNOME.
• QDirStat — GUI similar to WinDirStat.

Example: find large files and review

1. sudo du -ah /home/username | sort -rh | head -n 30 — show top 30 largest items.
2. Inspect with ls -lh or open in your file manager.

Example: finding duplicates with fdupes

1. fdupes -r /home/username — list duplicates.
2. To interactively delete: fdupes -rdN /home/username (dangerous — test first).

Malware scanning

• ClamAV — popular open-source scanner:
  • Install: sudo apt install clamav
  • Update DB: sudo freshclam
  • Scan: clamscan -r --bell -i /path/to/scan
• For Windows-infected files stored on Linux shares, ClamAV is useful but Linux-focused threats are rarer.

---

Cross-platform best practices

• Back up before deleting anything. Use Time Machine (macOS), File History/OneDrive (Windows), or rsync/duplicity/Deja Dup (Linux).
• Work in stages: identify large files → find duplicates → scan for malware → archive or delete.
• Use checksums for high-certainty duplicate detection: generate SHA256 hashes of suspect files and compare.
  • Example (Linux/macOS): sha256sum file1 file2
• Automate periodic scans: Task Scheduler (Windows), cron/launchd (Linux/macOS) for recurring maintenance.
• Keep system and anti-malware tools updated.

---

Example workflows

Quick clean (all platforms)

1. Visualize disk usage (WinDirStat / DaisyDisk / Baobab).
2. Move or delete obvious large files.
3. Run a duplicate finder to reclaim space.
4. Run malware scan on suspicious folders.
5. Back up important cleaned data.

Deep clean before backup

1. Create a full backup snapshot.
2. Use file-size and duplicate scans to reduce total data.
3. Re-run backup with trimmed dataset.

---

Safety checklist before deleting files

• Confirm file ownership and last-used date.
• Check file contents when in doubt (open or preview).
• Move items to a temporary “Quarantine” folder for 30 days before permanent deletion.
• Use versioned backups so accidental deletion can be recovered.

---

Short recommended tools summary

• Windows: WinDirStat, Duplicate Cleaner, Malwarebytes
• macOS: DaisyDisk, Gemini 2, Malwarebytes
• Linux: du, fdupes, rmlint, ClamAV, QDirStat

---

Scanning folders is a straightforward way to reclaim space, reduce clutter, and improve security. Apply platform-specific tools and a careful, staged process to avoid accidental data loss.