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How to shrink files without losing anything.

By Grant and Brad, who make Pangalin's apps · Updated 14 October 2026

Some files take far more space than they need to: logs, text exports, uncompressed audio, Photoshop and TIFF images. Pangalin Space Manager's Shrink rewrites them with Apple's built-in file compression. Each file stays where it is, keeps its name, and opens exactly as before, in every app. Nothing is deleted and nothing goes to the Trash.

What it does to your files

• It's Apple's own compression. Pangalin Space Manager makes a compressed copy with macOS's ditto tool, checks how much smaller it is, and only then swaps it in for the original. Apps read the file as normal; macOS uncompresses it as it's read.
• A file is kept compressed only if it really shrinks. If the copy saves less than 5%, the original is left untouched, and the file isn't offered again unless it changes.
• Editing a file later returns it to full size. That's how this kind of compression works, so Shrink only offers files you haven't changed in a while.

Shrink some files

1. Scan your startup disk, then choose Go › Free Up Space (⌘2). Under More ways to free space, click Shrink. It's shown when Pangalin Space Manager has found something to shrink. You can also choose Go › Tools (⌘6) and click Compress files.
2. Look through the list. Each row says where the file is and when it was last changed. The biggest files come first.
3. Tick the files you want to shrink, or tick none to shrink them all. Then click Compress … (for example Compress all 12 — 3.4 GB on disk now).
4. Read the confirmation. Pangalin Space Manager measures a sample first and tells you how well this data actually compresses. Click Compact all, or Cancel.
5. Wait while it works. The progress window lists each file with its size before and after, and what it saved.

Tools › Compress files opens Shrink as a page of its own. There the main button reads Compact all …, and each row has a Compact button to shrink one file at a time. Both ask you to confirm first.

What it offers

On your startup disk, Shrink looks in your Desktop, Documents, Music and Pictures folders for files that are:

• over 20 MB
• unchanged for at least 90 days
• of a type that usually compresses well: text, logs, CSV, JSON, XML and Markdown; HTML, RTF and Word .doc files; property lists; databases (.sqlite, .db); Photoshop, TIFF and BMP images; WAV and AIFF audio; MIDI files; Ableton Live sets, FL Studio projects and Vital presets; Final Cut XML and XMP sidecars

Photos, music and video in compressed formats (such as JPEG, HEIC, MP3, AAC and MP4) aren't offered, because they're compressed already and wouldn't get smaller.

When you scan another drive or a folder, files of the same types over 100 MB (drive) or 10 MB (folder) that haven't changed in 90 days are offered too.

What it leaves alone

• Anything on your Never Clean list, or inside a folder you've protected
• On your startup disk, anything inside apps, the Photos library, or node_modules, Pods, .build and target folders
• Files that are hard-linked to another place, because rewriting them would break the link
• Files that are already compressed
• Drives that aren't formatted APFS or Mac OS Extended (HFS+), such as exFAT or MS-DOS (FAT) drives. Shrink says so instead of showing an empty list.
• Files Pangalin Space Manager moved to an external drive, so the shortcuts to them keep working

Shrink works on files, not whole folders.

How much it saves

These kinds of files typically shrink by 30–70%, but it depends on what's inside them. Before you confirm, Pangalin Space Manager measures a sample of your files and shows an estimate. Afterwards, the progress window shows the real saving for each file, and only that real saving is counted.

Undo a shrink

Changed your mind? While Pangalin Space Manager is open, choose Edit › Undo Shrink (⌥⌘Z). It returns the files to full size with Apple's own afscexpand tool. Pangalin Space Manager checks first that there's room, because the files need back the space they saved; if there isn't, nothing changes. Undo is free, with or without a licence.

After you quit, the files stay compressed. That does them no harm: they keep opening exactly as before, and any file you edit returns to full size by itself.

Free allowance and licence

Shrinking counts towards your free 5 GB on each Mac, by the space it actually saved. Before a run starts, Pangalin Space Manager checks there's enough of your allowance left for it. Once you've used the 5 GB, shrinking more needs a licence, which is $25 a year. Scanning and seeing the list are always free.

Related guides

• Free up space safely
• Merge duplicates without deleting them
• See what you did and undo it
• Your free 5 GB, explained

Checked against Pangalin Space Manager 3.48.1, 14 October 2026.