Unable to back up files on Mac

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Never reaching 100% backed up is a key indicator that the CrashPlan app cannot back up one or more files. This troubleshooting article describes how to identify files included in your file selection that cannot be backed up on a Mac.

This article focuses on problems with individual system files not backing up. If your personal files are not backing up, it may be due to Apple privacy restrictions introduced in macOS Catalina 10.15 and macOS Mojave 10.14. See macOS not backing up files with personal data in CrashPlan for more details.


CrashPlan app running on a Mac

Under the hood

Typically, when files fail to back up on a Mac, it's due to the type of files selected for back up. Many of the files that cannot back up are located in the following folders:

  • /Library
  • /System
  • /Applications
  • /Users/<User>/Library

Files located in these folders contain system files that your device needs to operate. The CrashPlan app is designed to back up and restore personal files, not system and application files. If your backup file selection includes these locations, it could interfere with the priority your crucial files are backed up.

For example, files found in your Library folder are mostly temporary or cache files. The CrashPlan app prioritizes the most recently changed files first. This causes the CrashPlan app to spend too much time trying to keep up with constantly changing cache files (like your web browser cache). This can hinder the progress of more important files you truly want backed up.


You can use either of the methods below to identify which files are failing to back up.

 Troubleshoot inaccessible log folder

Determining what files are not backing up requires you to have access to CrashPlan log files. If you are unable to access the CrashPlan log files, you must alter the permissions of the log folder to enable access.

Determine what's not backing up (basic)

  1. Open the Finder.
  2. Press Command+Shift+G, and paste the following file path into the dialog:
    • Installed for everyone: /Library/Logs/CrashPlan
    • Installed per user: ~/Library/Logs/CrashPlan
  3. Press Enter.
  4. Open the backup_files.log.0 file with TextEdit.

This document lists every file that the CrashPlan app has backed up. However, any log lines beginning with a "W" signify a file the CrashPlan app wasn't able to back up at that time.

Determine what's not backing up (advanced)

  1. Open Terminal.
  2. Enter the following command. This command lists any file that failed to back up with the CrashPlan app:
    • Installed for everyone:
      grep "^W" /Library/Logs/CrashPlan/backup_files.log.0 | less
    • Installed per user:
      grep "^W" ~/Library/Logs/CrashPlan/backup_files.log.0 | less 

Recommended solution

Modify the file selection to include only personal files.

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