The Metadata Files: .DS_Store and ._AppleDouble

Every Mac user eventually notices them: .DS_Store files appearing in directories, ._ prefix files cluttering USB drives, and mysterious metadata files showing up in archives. These files serve legitimate purposes but can be annoying when they leak into version control or cross-platform file sharing.

.DS_Store Files

What They Are

.DS_Store (Desktop Services Store) files are created by Finder to store custom folder attributes:

• Window position and size
• Icon positions (when using icon view)
• View settings (icon/list/column/gallery view)
• Background color or image
• Sort order and column widths
• Custom icons

# Find .DS_Store files
$ find ~/Documents -name '.DS_Store' -type f 2>/dev/null | head
/Users/david/Documents/.DS_Store
/Users/david/Documents/Projects/.DS_Store
...

# View basic info
$ file .DS_Store
.DS_Store: Apple Desktop Services Store

# Size is usually small
$ ls -la .DS_Store
-rw-r--r--@ 1 david  staff  6148 Jan 15 10:30 .DS_Store

.DS_Store Contents

The file format is proprietary binary, but tools exist to examine it:

# Install ds_store Python library
$ pip install ds_store

# Or use a basic hex dump
$ xxd .DS_Store | head
00000000: 0000 0001 4275 6431 0000 3000 0000 0800  ....Bud1..0.....
00000010: 0000 2000 0000 0008 0000 0000 0000 0000  .. .............
...

The file contains:

• File/folder names in the directory
• Per-item display settings
• Finder view preferences
• Spotlight comments (sometimes)

Preventing .DS_Store Creation

On Network Volumes

Finder can be configured to not create .DS_Store on network drives:

# Prevent on network volumes
$ defaults write com.apple.desktopservices DSDontWriteNetworkStores true

# Prevent on USB volumes
$ defaults write com.apple.desktopservices DSDontWriteUSBStores true

# Restart Finder to apply
$ killall Finder

This doesn’t prevent local .DS_Store creation—only network and USB volumes.

Globally (Not Recommended)

There’s no supported way to prevent local .DS_Store creation without breaking Finder functionality.

Cleaning Up .DS_Store

# Delete .DS_Store files in current directory tree
$ find . -name '.DS_Store' -type f -delete

# Dry run first (just show what would be deleted)
$ find . -name '.DS_Store' -type f -print

# Delete from a specific path, including hidden directories
$ find /path/to/folder -name '.DS_Store' -delete

.DS_Store and Git

These files should almost always be gitignored:

# Add to global gitignore
$ echo '.DS_Store' >> ~/.gitignore_global
$ git config --global core.excludesfile ~/.gitignore_global

# Add to project .gitignore
$ echo '.DS_Store' >> .gitignore

# Remove already-tracked .DS_Store files
$ git rm --cached $(git ls-files -i --exclude-standard '*.DS_Store')
$ git commit -m "Remove .DS_Store files"

AppleDouble Files (._prefix files)

What They Are

When macOS copies files to filesystems that don’t support extended attributes (FAT32, exFAT, SMB shares, etc.), it creates companion files with ._ prefix:

# Copy to FAT32 drive
$ cp photo.jpg /Volumes/USB_DRIVE/

# Results in:
$ ls -la /Volumes/USB_DRIVE/
-rwxr-xr-x  1 david  staff  1048576 Jan 15 10:30 photo.jpg
-rwxr-xr-x  1 david  staff     4096 Jan 15 10:30 ._photo.jpg

What They Contain

AppleDouble files store:

• Extended attributes that couldn’t be preserved
• Resource forks (if present)
• Finder metadata
• ACLs

# View what's in an AppleDouble file
$ xattr -l ._photo.jpg
# (Shows nothing - attributes are encoded in file content)

# Decode structure (basic view)
$ xxd ._photo.jpg | head
00000005 26 00 02 00 00 00 00 00  00 00 00 00 00 00 00 00  |&...............|
00000015 00 00 00 00 00 00 00 00  00 02 00 00 00 09 00 00  |................|
...

When They Appear

• Copying to FAT32/exFAT USB drives
• Copying to SMB/CIFS network shares
• Creating ZIP files (sometimes)
• Copying to NFS shares without xattr support
• Burning to data CDs/DVDs

The dot_clean Command

macOS provides dot_clean to merge AppleDouble files:

# Merge AppleDouble files back into their parent files
# (Only works when copying back to APFS/HFS+)
$ dot_clean /Volumes/USB_DRIVE/

# Merge and remove AppleDouble files
$ dot_clean -m /Volumes/USB_DRIVE/

# Verbose output
$ dot_clean -v /Volumes/USB_DRIVE/
Merging ._photo.jpg
...

Cleaning Up AppleDouble Files

# Find all AppleDouble files
$ find /Volumes/USB_DRIVE -name '._*' -type f

# Delete them
$ find /Volumes/USB_DRIVE -name '._*' -type f -delete

# Delete .DS_Store AND AppleDouble files
$ find /Volumes/USB_DRIVE \( -name '.DS_Store' -o -name '._*' \) -delete

Preventing AppleDouble Files

Use ditto with –norsrc

# Copy without resource forks/AppleDouble
$ ditto --norsrc source.txt /Volumes/USB_DRIVE/

# Copy entire directory
$ ditto --norsrc ~/Documents/folder /Volumes/USB_DRIVE/folder

Strip Attributes Before Copy

# Copy then strip
$ cp file.txt /Volumes/USB_DRIVE/
$ xattr -c /Volumes/USB_DRIVE/file.txt
# This removes the need for AppleDouble companion

Use Archive Formats

When sharing files, use formats that either:

• Don’t preserve Mac metadata (simple tar, zip)
• Explicitly preserve it (tar with –xattrs, ditto archives)

# Create cross-platform-friendly tar
$ tar -cvf archive.tar files/
# No metadata preserved, no ._files

# Or strip metadata first
$ find files/ -name '._*' -delete
$ find files/ -name '.DS_Store' -delete
$ tar -cvf archive.tar files/

__MACOSX Folders in ZIP Files

When Finder creates ZIP files, it may include a __MACOSX folder:

# Create ZIP with Finder
$ cd ~/Documents
# Right-click folder → Compress "folder"

# Extract on Windows/Linux reveals:
# folder/
# __MACOSX/
#   folder/
#     ._file1.txt
#     ._file2.txt

Creating Clean ZIPs

# Use zip command with exclusions
$ zip -r archive.zip folder/ -x "*.DS_Store" -x "__MACOSX/*" -x "._*"

# Or use ditto to create clean ZIP
$ ditto -c -k --sequesterRsrc --keepParent folder archive.zip
# --sequesterRsrc puts resource forks in __MACOSX (standard Mac behavior)

# For truly clean ZIP (no Mac metadata at all):
$ cd folder && zip -r ../archive.zip . -x "*.DS_Store" -x "*.git*" -x "._*"

Extracting and Cleaning

# Extract ZIP
$ unzip archive.zip

# Remove Mac metadata
$ find . -name '__MACOSX' -type d -exec rm -rf {} +
$ find . -name '._*' -type f -delete
$ find . -name '.DS_Store' -type f -delete

Best Practices

For Version Control

Standard .gitignore entries:

# macOS metadata
.DS_Store
.AppleDouble
.LSOverride

# Icon must end with two \r
Icon

# Thumbnails
._*

# Files that might appear in the root of a volume
.DocumentRevisions-V100
.fseventsd
.Spotlight-V100
.TemporaryItems
.Trashes
.VolumeIcon.icns
.com.apple.timemachine.donotpresent

# Directories potentially created on remote AFP share
.AppleDB
.AppleDesktop
Network Trash Folder
Temporary Items
.apdisk

For File Sharing

When sharing files with non-Mac users:

1. Clean before sharing:

find /path/to/share -name '.DS_Store' -delete
find /path/to/share -name '._*' -delete

2. Use appropriate tools:

# For cross-platform ZIP
zip -r archive.zip folder/ -x "*.DS_Store" -x "._*"

3. Configure Finder:

defaults write com.apple.desktopservices DSDontWriteNetworkStores true
defaults write com.apple.desktopservices DSDontWriteUSBStores true

For External Drives

If you regularly use drives with non-Mac systems:

# Configure once
defaults write com.apple.desktopservices DSDontWriteUSBStores true

# After use, clean up
dot_clean /Volumes/DRIVE_NAME
find /Volumes/DRIVE_NAME -name '.DS_Store' -delete
find /Volumes/DRIVE_NAME -name '._*' -delete

Summary

macOS metadata files serve real purposes but require management:

Key commands:

• find . -name '.DS_Store' -delete — Clean .DS_Store files
• find . -name '._*' -delete — Clean AppleDouble files
• dot_clean /path — Merge AppleDouble files back
• defaults write com.apple.desktopservices DSDontWriteUSBStores true — Prevent on USB

These files are a side effect of macOS’s rich metadata system—useful locally but often unwanted when files leave the Mac ecosystem.