In version 4.3 and later, CrashPlan supports the back up of encrypted files, folders, drives, and filesystems that are run at a system or user level.
CrashPlan versions 4.2 and earlier only supports encrypted files, folders, drives, and filesystems that are run at a system level. In other words, they are not being configured and run in a user space. You may run into issues with user-level encrypted files if credentials aren't readily available to CrashPlan.
CrashPlan has full FileVault and FileVault 2 support. For Mac OS X versions 10.4, 10.5 and 10.6, CrashPlan must be installed per user. See Using CrashPlan With FileVault for installation instructions.
FileVault 2, included with OS X Lion and later, can use the per user CrashPlan app installation option or be installed for everyone.
There is an option in Truecrypt enabled by default called preserve timestamps of file containers. When enabled, Truecrypt retains the file timestamp from initial file creation. Essentially, it looks like the file has never changed and CrashPlan won't back up the changes. If you disable this option, the file timestamp changes when files are modified, which allows CrashPlan to back up the changes. Although this is an unsupported process, we have instructions available for interested users.
BitLocker drive encryption
Windows BitLocker Drive Encryption provides full drive encryption. Since BitLocker runs at a drive level, CrashPlan is able to back up drives protected by BitLocker when the drive is in an open or unlocked state (i.e., decrypted at the drive level).
However, when the drive is locked (i.e., encrypted), CrashPlan can't back up the files and may report the drive as missing. By default, CrashPlan never removes missing or deleted files from your backup archive; you can confirm your deleted file settings from Settings > Backup > Frequency and versions. If the CrashPlan app reports the drive as missing when it is unlocked, you may need to run a file verification scan.
Because CrashPlan backs your files up when they are unencrypted, they can only be restored as unencrypted files. You can restore these files on other computers or using the CrashPlan web app without worrying that the files will restore in an encrypted state.
Windows Encrypting File System (EFS)
Windows EFS runs in a single user space. Version 4.3 and later of the CrashPlan app supports the backing up of files protected by Windows EFS when installed per user.
Backing up files, folders, or drives encrypted with Windows EFS is not officially supported in CrashPlan versions 4.2 and earlier. You can configure Windows to allow CrashPlan to back up files encrypted with Windows EFS; however, this is an unsupported process that our Customer Champion team cannot assist you with. To back up files encrypted with Windows EFS, you must install CrashPlan as the user who owns the encrypted files instead of the default installation as the SYSTEM user. See Enabling Windows EFS Support for more information.
If you're using another encryption product with CrashPlan and have questions or would like to share your knowledge or discuss, please visit our User Forums.