Unable to back up files (Windows)


When the Code42 agent is unable to back up a file, the History window displays the message "unable to back up n files." This most commonly occurs when the Code42 agent is trying to back up a file that is open, encrypted, or lacking proper permissions. This article addresses how to identify which files are not backing up and how to resolve the issue.


The Code42 agent on Windows


When the Code42 agent is unable to back up a file, the History window displays the message "Unable to backup n files" (where n is the number of files the Code42 agent is unable to back up).


Identify problem files

Follow these steps to identify the specific files that are not backing up:

  1. Open a file browser and paste the following location into the address bar:
    • Installed for everyone: C:\ProgramData\CrashPlan\log
    • Installed per user: C:\Users\<username>\AppData\<Local or Roaming>\CrashPlan\log
  2. Open the backup_files.log.0 file in a text editor. 
    Most problem files can be found towards the end of the log file.
  3. A file failing to back up is noted with a "W" at the start of the line:
    W 01/06/13 12:00PM 42  - C:\Users\John\Blackberry\Backup\BlackBerry Tour 9630-1.ipd

    A file backing up successfully is noted with an "I" at the start of the line:
    I 01/06/13 12:00PM 42 50cd0afdb853e65f1f47c31407ce9a4a 0 C:\Users\Jill\Documents\Outlook Files\outlook.pst (200483653) [1,0,200483653,0,0,0,0]

Recommended solutions

Once you've identified the problem files, review the information below to determine if the files fit into one of these categories. Additional troubleshooting information is provided for each category.

May be unable to back up
Unable to back up

System files

The Code42 agent is designed to back up user files (documents, photos, etc.). It is not designed to back up your operating system or applications. For additional information, see our guide about choosing what to back up.

Application files

By default, the Code42 agent backs up your user folder, which contains the AppData folder for your computer. Certain files inside AppData can fail to back up with the Code42 agent because they:

  • Are open and locked by the application that created them.
  • Were not created with the correct permissions for the Code42 agent to back them up.

If the files that are failing to back up are located in the AppData folder, review our guidelines for backing up the AppData folder.

Open files and databases

While the Code42 agent backs up open files by default, it does not have application-specific "hooks" to back up files that are always being written to (SQL databases, virtual machines, Act! databases, etc.). To back up these files:

  1. Close the identified files and the applications using those files.
  2. Open the Code42 agent.
  3. Select Run backup now to retry backing up the file.
Backing up open files and databases
To increase the likelihood that the Code42 agent can consistently back up and recover large open files, use application-specific tools to dump/export a snapshot of the internal state to a file. See Back up open files and databases for additional details.

System permissions

In the default Windows installation (installing the Code42 agent for everyone on the device), the Code42 agent relies on the system user's read/write permissions to access your files. However, there are some files or folders the system user may not have permission to access. If you need to back up these files or folders, follow our tutorial to add the system user to the permissions list.

Windows Encrypting File System

You can tell whether or not a file is encrypted with EFS by the green label in a file browser.

Encrypted Folders

In order to back up files encrypted with EFS, you must install the Code42 agent per user. Alternatively, you can remove file encryption using the steps below:

  1. Right-click the encrypted file.
  2. Select Properties.
  3. From the General tab, select Advanced.
  4. Deselect the option to Encrypt contents to secure data.


In Windows 8.1, Microsoft introduced smart files to conserve local hard drive space. If you include your OneDrive folder in your backup selection, you may need to make your files available offline before they can be backed up.

VSS snapshots

When the Code42 agent tries to access open files, the Windows Volume Shadow Service (VSS) pauses the application writing to the file and creates a snapshot of it. Sometimes these snapshots don’t get deleted after use. Since VSS limits the permissions on those snapshots, the Code42 agent can't back them up. See Understand and troubleshoot backing up open files with Windows VSS for additional details.

Here is an example VSS snapshot:


To clear VSS snapshots out of your system, do the following:

  1. Go to the Windows Start menu
  2. Search for cmd
  3. Right-click on cmd.exe and select Run as Administrator
  4. In the command prompt, enter this command:
    vssadmin delete shadows /all
  5. Press Enter