External storage used to mean floppy disks, CDs and DVDs. Today, we have external hard drives like the massive Samsung 16TB SSD and the popular Western Digital My Passport. Even with advances in external storage reliability, though, the safest bet is to keep data copies in the cloud, and in this article, we’ll run down the best online backup for external hard drive solutions available.

That reason we recommend cloud backup is because external drives can break or crash just like your computer drive can. If it’s an SSD you’re using, the rate of failure is far below one percent, but SSDs are prone to data errors more than HDDs. Plus, any external drive can be stolen.

Before our online backup rankings, let’s dive into the criteria that we used to make our picks. If you’re looking for storage instead of backup (see here on the difference), check out our cloud storage comparison chart for some ideas.

Best Cloud Backup for External Hard Drive 2019

cloudwards rating
$ per month
top features

Starts from $ 600 per month

What Makes the Best Online Backup for External Hard Drives

Backing up your files is great, but backing them up for little money is better, which is why we put an emphasis on value in putting together our list. Online backup services vary on how many plans are offered and for what price, with some even offering unlimited backup space.

Once sent to the cloud, you want your data to be snug and secure. Therefore, security is our next criterion. We’ll see what kind of encryption is offered and whether files are protected both in-transit and at-rest.

Not every service offers it, but we like to see zero-knowledge encryption, too, as it prevents anyone other than you from reading your data. Another key security feature is two-factor authentication, useful should your password be cracked or stolen.

In addition, we like overall user experience to be straightforward. An easy-to-use client and features like backup-by-file type help.

Last, a good, stable connection is necessary to perform backups. We don’t want it to hang, drag (more than is appropriate) or fail. Backup speed and reliability is mostly dependent on the infrastructure of the backup service, but also your ISP and how close you are to the servers.

With our criteria laid out, let’s take a look at our top pick for external drive backup, Backblaze.

Best Online Backup for External Drive Briefing: Backblaze

Backblaze has been in the business of providing computer backup since 2007, and it’s one of the most popular online backup services today. It’s near the top of our list of best online backup solutions overall, in fact.

Like the user experience, Backblaze has a simple pricing scheme. There’s only one plan for home backup, and it gives unlimited backup for one computer for just $5.

You can also backup unlimited external hard drives under that $5 plan. That, of course, means huge value for those with stacks of drives (note, however, that Backblaze doesn’t allow NAS device backup.)

Backblaze has most of the security features that we like to see, and that includes an option for private encryption. If it’s disabled, Backblaze holds on to your encryption key. Otherwise, you have the key. However, recovering those encrypted files does require that you send Backblaze your passphrase for decryption (the company supposedly erases record of it afterward).

Besides private encryption, your files are encrypted at-rest using AES 128-bit in the Backblaze cloud. That encryption protocol is practically uncrackable, but we prefer its beefier cousin, AES 256-bit. In-transit files are further protected with SSL.

Backblaze data centers retain multiple copies of your files on multiple servers for redundancy using a RAID setup. Those centers are also hardened against natural disaster and secured against physical and virtual intruders.

To prevent malicious individuals from exploiting your weak password, Backblaze gives you the option to enable two-factor authentication (2FA), too. There’s even an option to require a security code every time you log in.

Running backup using the desktop client is a breeze. In fact, Backblaze provides the easiest user experience of any service we’ve tested. You don’t need to manage how much or even what data you’re backing up because Backblaze pretty much takes it all (except system and temporary files). There’s no need to create a backup plan; everything is done automatically.

Other Reasons Why We Like Backblaze

Initial backups inevitably take a long time but some services manage file copying better than others. It helps that Backblaze doesn’t limit upload and download speeds. The only factors in play should be the distance to the server in California, encryption and file compression. On top of that, you can speed things up by increasing the number of backup threads you have running.

Backblaze Restore Drives

Backblaze provides unlimited backup for cheap, allows you to backup unlimited external drives, has great security, achieves good speeds and gives you a fluid user experience. It’s no surprise that we’ve placed it first on our list. Read more about Backblaze and its features in our Backblaze review.


  • Unlimited backup
  • Low cost
  • External HD backup


  • Limited to one computer
  • Private encryption not truly end-to-end
Starts from $ 458 per month for Unlimited GB
Save 24 %


IDrive is based in the San Fernando Valley. The company was launched way back in 1995, and that makes it a true veteran. The service is not frail with old age but rich with experience. It separates itself from its competitors by offering backup for unlimited devices.

Unlimited devices include not only computers but external drives, tablets and smartphones. Data, however, is capped, unlike with Backblaze. There are two plans: one with 2TB and the other 5TB of backup space.

You also get 2TB or 5TB of sync space with your plan that allows you to play around with 4TB or 10TB of actual space. In addition, there’s a free plan that will give you 5GB of free space. That’s enough if you want to try the service before deciding to invest long term (subscription are one or two years).

You also get 2TB or 5TB of sync space with your plan that allows you to play around with 4TB or 10TB of actual space. In addition, there’s a free plan that will give you 5GB of free space. That’s enough if you want to try the service before deciding to invest long term (subscription are one or two years).

Data sent to the IDrive cloud is encrypted using the AES 256-bit algorithm, both at-rest and in-transit. IDrive keeps the key to decrypt your data, but you can retain your key if you wish. However, you’ll need to opt-in for private encryption prior to running your first backup.

To our surprise, two-factor authentication is not available to protect you against stolen passwords. Make sure you use a strong password because of that (need help with that?).

IDrive servers are located in secure data centers in the United States. They are built to endure natural disasters and fires thanks to racks, raised floors, cooling zones, etc. Surveillance, motion sensors and alarms will protect against intruders.

The desktop client doesn’t provide a simple user experience. Unlike the unlimited backup services, IDrive has a cap on 2TB or 5TB, which means you may have to manage your backup space, especially with external drives.

Other Reasons Why We Like IDrive

Initial uploads can drag with IDrive. Unfortunately, there’s no setting to initiate multi-threaded backups like with Backblaze. However, IDrive does have a free courier backup service that can help out, which is called IDrive Express. It’s available for downloads as well.

IDrive isn’t expensive, it allows you to backup unlimited devices, including external drives, and protects your data with private encryption. What it doesn’t do is provide two-factor authentication and a simple user experience. Critical to external drive backup, you also don’t get unlimited backup.

Once we do the math, it’s clear IDrive ranks behind Backblaze for external drive use, but it’ll still do the trick for most people. If you want an in-depth look at the service, head over to the IDrive review.


  • Unlimited device backup
  • Inexpensive plans
  • Private encryption


  • Harder to use than Backblaze
  • No unlimited backup plan
  • Not multi-threaded backup
Starts from $ 458 per month for Unlimited GB
Save 24 %


Even though CrashPlan withdrew from the field of consumer backup in August 2017, its business plan still makes for a good investment if you need to backup your external drive and can be used by home consumers.

Each computer backed up costs $10 per month and you get unlimited backup. With that, you can also backup unlimited external drives. In addition, you’re always charged monthly, so you can cancel at any time, unlike with IDrive. The price doesn’t seem great when compared to Backblaze at half the cost, but relative to most services, CrashPlan is still a very good deal.

CrashPlan features end-to-end and at-rest encryption. Usually, the company will hold your encryption keys, but just like with our top two picks, you can opt for private encryption. Whether or not you enable it, be sure to create a strong password, however, as CrashPlan doesn’t offer two-factor authentication.

You need only a couple of minutes to install the client and sign in. The client isn’t hard to use, but backup operations could be simpler. It doesn’t backup based on type like Backblaze; you’ll have to build your backup plan manually, even though you’re getting unlimited backup.

Other Reasons Why We Like CrashPlan

CrashPlan doesn’t achieve good backup speeds. You could improve that by disabling file compression, encryption and deduplication processes. That’s not recommended but deduplication does seem to be the main culprit here.

Throttling is available if backing up is taxing your computer, and you can also set the client to increase the speed when you’re away. Read more about CrashPlan in our CrashPlan review.


  • Unlimited backup
  • Backup external drive
  • Retains deleted files indefinitely


  • Doesn’t backup by file type
  • No two-factor authentication
  • Slow

Starts from $ 600 per month

Acronis True Image

Acronis has been in the backup business since 2003, and that kind of experience is evident with its newest release, Acronis True Image 2018.

With Acronis True Image, you get the option to purchase a lifetime plan, but it comes with several caveats so we recommend getting a monthly plan. There are two annual plans to choose from, Advanced and Premium.

Advanced gives you 250GB of backup space for $49.99 or 500GB for $69.99. Premium starts with 1TB for $59.99 and finishes with up to 5TB for $259.95. Any plan can be used to backup one computer and as many external drives as you need.

Acronis True Image lets you scramble files before sending them to the Acronis Cloud by clicking “encrypt backup” when creating your backup plan. The trick is that the text is easy to miss. You’re required to enter a password while doing so, and only you know it. The files remain encrypted in the cloud until you decrypt them, making True Image zero-knowledge.

The level of encryption is AES 256-bit. Data in transfer is protected with TLS/SSL. A novel feature that Acronis employs is Acronis Active Protection which monitors for ransomware attacks. If it fails to protect you, you can rely on versioning to help you retrieve your ransomed files. There’s no two-factor authentication, though.

Besides software protection, data centers use biometric scanning, key cards, patrols and monitoring to ensure there are no breaches. Your data is also stored on multiple servers and those servers are protected against natural disasters and fires.

The desktop client is easy to navigate but the text is a bit small. The client gives you the option to simply backup everything which is slower and takes more space, so probably not something you’ll want to do with multiple external drives.

Other Reasons Why We Like Acronis True Image

Acronis doesn’t struggle with slow initial backups like other backup services do. One of the most compelling reasons to justify its higher cost is that speed. Backing up and recovering a 1GB folder took only 15 minutes in our tests (though those tests weren’t conducted using external drives).

You can set a limit for the backup speed or switch between “optimal” and “maximum.” Our tests actually used optimal, speeds would have been even better (presumably) set to maximum. To see the actual numbers and other features, read our Acronis True Image review.


  • Exceptionally fast backup
  • Private end-to-end encryption
  • Disk imaging & cloning


  • No two-factor authentication
  • Expensive
Starts from $ 417 per month for 250 GB


Unlike most backup services, Carbonite offers three plans instead of one for unlimited storage: Basic, Plus and Prime. Carbonite Plus is the most popular plan because it supports external hard drive and automatic video backup, unlike Basic. Plus is a bit expensive, however, at $111.99 annually.

Prime users get free courier recovery service, but unless you plan to do full regular backups it’s not worth the money. All three plans are billed annually. There’s a discount of five percent if you purchase any plan for two years in advance or 10 percent if you go three. You can try the service out, first, with a 15-day trial, too.

Carbonite protects all data stored on its servers with 128-bit AES encryption. It holds the key for that encryption but you can enable private encryption. If enabled, Carbonite uses 256-bit AES, instead. Completing its mostly foolproof security profile, Carbonite has strong password requirements and an option for two-factor authentication.

The Carbonite desktop client (Windows or macOS) is easy to install. Once installed, you only have one step when initiating backup since most of the process is automated. The only match for its simplicity is Backblaze. Carbonite even color codes your files (if you have that option enabled) while backing them up so you can check their status more easily.

Other Reasons Why We Like Carbonite

There are no other reasons as the backup process is much slower than the competitors like Backblaze and IDrive. If you’d like to see the details about speed and other features, read our in-depth Carbonite review.


  • Unlimited backup
  • Backup by file type
  • External HD backup


  • Very slow
  • No monthly subscriptions
  • A little expensive
Starts from $ 600 per month for Unlimited GB

Final Thoughts

Backblaze represents a great choice when backing up external hard drives because you get unlimited storage and an unlimited number of drives to backup, in addition to one computer. Unless you’re looking for NAS backup, too, we definitely recommend considering this service first for external drive backup by giving the 15-day free trial a go.

CrashPlan and Carbonite are other options with unlimited storage and external drive support, making them decent Backblaze alternatives for that task if you don’t mind paying a little more.

IDrive meanwhile, supports backup of unlimited devices, including computers, mobile devices and hard drives, while Acronis True Image is a good option for those who need both external drive support and fast backup speeds.

Do you use another service for backing up your external drives? Is there something we forgot? Tell us about it in the comments below. Thank you for reading.

Starts from $ 600 per month

One thought on “Best Online Backup for External Hard Drives”

  1. Whatever you do, do not use Backblaze, they have trashed my backed up data because my hard drive failed, I didn’t realise this and if a hard drive os not connected for 30 days they just wipe your data, two and a half years of professional photography work is lost. I am heartbroken.

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