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Exclude or filter files using file type and regular expressions

Applies to:
  • Code42 CrashPlan (previously CrashPlan PROe)


Certain files and file types can be globally excluded from a backup without having to modify the file selection by deselecting individual files and folders. These exclusions can be added either by file type or by using regular expressions (regex). This tutorial explains how to configure your backup using both file type and regular expression exclusions.


  • Your administrator may prevent editing of file exclusions. This article assumes you have permission to create file exclusions.
  • If you have an existing backup, implementing a file exclusion will delete any files in your backup archive that match that exclusion.
  • Code42 is not responsible for data removed in this manner.
Backup sets and exclusions
Backup sets are an optional feature. If you use backup sets, special caution is needed when creating file exclusions. Specifically, file exclusions specified for any backup set impact all sets backing up to the same destination.

Example: Set A and Set B back up to an external hard drive destination. Set A has an exclusion indicating that files ending in .mp3 shouldn't back up. Even though the exclusion isn't specified for Set B, MP3s from this set will not back up to the external hard drive.

Common exclusions

Since many of the files below can be easily re-downloaded or installed, you can exclude them all together. This may decrease the initial upload duration.

  • Windows executable files (.exe)
  • Disc images (.iso)
  • Temporary files (.tmp)
  • OSX DS_Store files (.DS_Store)

Add exclusions by file type


  1. Open the CrashPlan app.
  2. Select Details.
  3. Click the backup set settings icon.
  4. Next to File Exclusions, select Change.
  5. Enter a file extension.
    For example, to exclude your music files, enter mp3 or .mp3.
  6. Click Add.
    Create additional exclusions, if desired.
  7. Click Save.

File exclusions

Add exclusions with regular expressions

A regular expression (regex) is a search pattern which locates files and folders containing a specific sequence of characters by comparing that sequence to absolute file paths on your device. Leverage the power of regular expressions to fine-tune and allow for more complex backup file exclusion rules.

Special character restrictions
Some special characters are treated differently or are restricted when used to create regular expressions:
  • The following characters cannot be used in CrashPlan regex exclusions: <, >, and '.
  • CrashPlan treats all file separators as forward slashes /.


  1. Open the CrashPlan app.
  2. Select Details.
  3. Click the backup set settings icon.
  4. Next to File Exclusions, select Change.
  5. Select Regular Expression.
    The example regex in the image below excludes any folder that starts with IMAP.
  6. Click Add.
    Create additional exclusions, if desired.
  7. Click Save.

file exclusions

Example 1 - exclude files that end with .mp3


In simple terms, this expression excludes:

  • A filename of any length, made up of any character(s), that ends with .mp3

Specific components of the expression are defined as follows:

  • The first dot (period) indicates the filename can contain any character, and the * indicates the filename can be any length (from a length of zero to infinity, or more accurately, up to your operating system's filename length limit).
  • The backslash (\) before the second dot indicates that dot should be evaluated literally as a dot (not as a character wildcard like the dot at the beginning of the expression). You may hear this described as "the dot in .mp3 is escaped with a backslash."



Any pattern beginning with (?i) indicates a case-insensitive search, so the example above will match files that end with .mp3 and .MP3 (as well as .Mp3 and .mP3).

Example 2 - exclude files and folders that start with temp


This expression excludes any file or folder name that begins with TEMP would be excluded from backups. For example, the following would be excluded by this expression:

  • C:\Windows\TEMP
  • C:\Windows\TEMP2
  • C:\Windows\TEMP.tmp
  • C:\Windows\security\TEMPLATES

In the above examples, note that other directories in the \Windows and \Windows\security folders that do not begin with TEMP would still be included. However, all subdirectories, or folders within the excluded folders, would be excluded as well.

External resources

There are many fantastic regex resources on the Internet. Here are a few of our favorites:

If you need help with your regular expressions, you might also try asking for help from other users in our User Forums.