External Hard Drives

During installation, Backblaze backs up any USB or Firewire hard drive that you have attached to your computer. You can also add external hard drives to Backblaze Computer Backup.

To be selectable for backup, a given drive must:  

• Have native read and write access by the operating system (for example, some utilities allow New Technology File System (NTFS) drives to be read/write accessible on macOS systems. Drives mounted in this way may be selectable, but they are not supported. Backblaze highly recommends that you do not attempt to back up these volumes.)
• Directly connect to the computer (USB, Firewire, Thunderbolt, eSATA, and others).
• Not be a Time Machine backup volume (macOS only).
• Not be mounted as a removable storage device as many flash, SD card, CD, DVD, Blu-ray, and some external SSDs do (Windows only).
• Be in working condition.

Multiple External Hard Drives

To ensure that all drives correctly update, you must ensure that your external hard drives are plugged in simultaneously as much as possible.

If you have multiple external hard drives, ensure that each drive is correctly selected. For more information about connecting external hard drives, see Back Up External Hard Drives for your specific operating system.

Unplugged or Failed External Hard Drives

Backblaze Computer Backup works best if you leave the external hard drive attached to your computer all of the time. However, Backblaze backs up external USB and Firewire hard drives that are detached and reattached as long as you remember to reattach the hard drive at least once every 30 days. If the drive is detached for more than 30 days, Backblaze interprets this as data that has been permanently deleted and securely deletes the copy from the Backblaze data center. The 30-day countdown is only for drives that have been unplugged. There is no countdown for local files.

When a drive is missing for 14, 21, and 28 days, Backblaze emails an alert to the account email on record.

When an external drive is plugged back in, it may take Backblaze two to four hours to schedule the files on the external drive to be scanned and backed up.

If your computer is going to be powered off or disconnected from the internet for an extended period of time, such as for a vacation, click here to learn how to protect your backed-up data.

Extended Version History and External Hard Drives

The best and easiest thing you can do to protect backed-up data long term is to enable Extended Version History.

You can extend the time that Backblaze retains your backed-up files by one year. You can also choose to keep everything that has been changed or backed up by upgrading to one of the Extended Version History plans. Click here to learn more about setting up Extended Version History. After you enable Extended Version History, everything is retained from that point until the time that you have chosen, including your external hard drives.

Renaming and Replacing an External Hard Drive

If you change the name of your external hard drive, you must reselect it for backup.

Backblaze detects any files that were uploaded. The software uses a process called "deduplication" in which files are digitally fingerprinted (checksummed) before they are sent to the server. When a file's fingerprint matches an already backed-up file, but you renamed or moved the file (including drive-to-drive), it is updated at the servers rather than retransmitted.