How to Backup an External Hard Drive?

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    Perhaps you’ve had your PC or Mac for several years now and filled up your hard drive, or maybe you do a lot of photo and video editing and need regular, easy access to additional storage? Either way, an external hard drive can be a great way of quickly and easily adding additional storage to a PC or Mac!

    how to backup external drive - drive and laptop

    Despite external hard drives being so quick and easy to set-up and make use of, something many people might forget to do is make sure their external hard drive is backed up correctly along with the rest of their devices. This means, without proper consideration, any data stored on external hard drives might not be fully backed-up and at risk of data loss!

    In this guide I will look at how to backup an external hard drive correctly, suggest some good services which can help you achieve this goal and also look at some very important considerations and peculiarities to be aware of!

    Looking for backup software?

    Are you looking for help and advice on choosing the best backup software for your PC or Mac? If so then be sure to check out our guide to choosing backup software which also contains a list of our favorite choices as tested here on!

    First, Check if Your External Drive is Backed-up

    If you have concerns about whether your external hard drive is being backed-up correctly, one of the first things you should do is open up your current backup software and check that the external drive is selected as a location to be included within the main backup set.

    Assuming this does check out ok and the external drive is included in the backup, the next thing to check is that the files on the external drive can be recovered correctly. The easiest way to do this is to recover a small sample of files originating on the external drive from your within backup software and make sure that they recover ok (and crucially can be accessed and are usable).

    Once you are happy that you external drive is included in your backup set and is working correctly (hence the test restore) then the next thing to do is check the external hard drive policies of your backup provider, this will, generally speaking, involve one of the following three options:

    1. If you use a cloud backup provider (a piece of backup software and cloud storage purchased together as a single subscription) then be sure to carefully check the providers policy on backing-up external drives.

    I have detailed some of these policies a little further down in this article but, generally speaking, some providers are very lenient when it comes to external drives whilst others impose very strict rules (for example, some providers will delete external drive backups if the drive in question is unplugged for more than 30 days).

    2. If you use backup software which supports choosing your own cloud storage (e.g. Backup Pro 15, Arq 7, Duplicati etc.) then you should have no problems in retaining external drive backups, even if the drive is left unplugged for long periods of time (just make sure the drive is being backed up correctly as discussed).

    3. If you use local backup software that backs up to, for example, a NAS system then you should not have to worry about the safety of your external drive backups should the external drive be removed for long periods of time. If you do make use of NAS then it is still advisable to look at backing up the NAS device itself to a provider such as Backblaze B2 or AWS S3 for extra safety (many top NAS manufacturers including QNAP and Synology support doing this).

    Backing-up an External Hard Drive to the Cloud

    One of the quickest and easiest ways to get your external hard drive backed up is to subscribe to a cloud backup provider such as Backblaze or Crashplan and make sure your external drive is included in the backup set (Backblaze will automatically include all connected drives unless instructed not to).

    adding external hard drive to backup set

    When using a cloud backup service It is important to make sure your external drive is included in the backup set as many services will not include external drives by default (with the notable exception of Backblaze mentioned above). As such, be extra vigilant when configuring cloud based backup software and ensure any external drive to be backed up are plugged-in and added to the backup set at time of initial set-up!

    Beware of the Un-plugged Drive Rule!

    Once you external hard drive is a part of your backup set you might now be forgiven for thinking it is fully protected, backed-up and that there is nothing further to worry about, right? Unfortunately this is not the case!

    One issue which seems to be common amongst many cloud storage providers is how they treat external hard drives which have been unplugged (or missing) for a certain period of time, often this treatment involves removing said devices from your backup set (and thus making them no longer protected or backed-up in the process).

    Whilst most cloud backup providers seem to have their own take on this situation, some of the more popular providers have rules such as those mentioned below:


    Backblaze automatically add any external drives to the backup set which is a great start, however, they will automatically remove (delete) any backed-up data from said drives if they are unplugged for a period of more than 30 days!

    More info can be found at the Backblaze external drive support page.


    Firstly, Carbonite does not automatically include external hard drives in their cloud backups nor do they allow such devices to be backed up on all of their plans (you must be subscribed to the Plus plan or higher to do this).

    Assuming you are on a sufficient plan and have manually specified an external hard drive be backed up, Carbonite will insist the drive is connected at least once every 30 days else this drive will be removed from the backup!

    You can get more information on the Carbonite policies by clicking here.


    Crashplan will allow the backing up of external hard drives, although they must be manually added to the default backup set to be included.

    Also, Crashplan will never delete any backed-up files form an external hard drive backup, regardless of how long the device might have been disconnected (providing the versioning settings for deleting old files is set to never, the default setting). More information can be found at the CrashPlan support Portal.

    NB – Crashplan also provide unlimited cloud storage per device meaning this can be a great service for backing up multiple, potentially very large external hard drives.

    Acronis True Image (Cloud):

    Acronis (via their True Image cloud subscription) allow external hard drives to be backed up to the Acronis cloud, they must, however, be manually selected within the backup set to be included.

    Once backed up, any external hard drives will remain backed-up in the cloud for as long as the subscription is active, even if they are unplugged for long periods of time.

    SpiderOak One:

    SpiderOak One supports backing up external hard drives providing they are added to the backup set manually. If an external hard drive is removed from the PC then the files will forever remain backed up whilst the subscription is still active (unless otherwise manually deleted).

    More information can be found at the SpiderOak help portal by clicking here.

    iDrive backup:

    iDrive Backup supports backing up external hard drives providing they are added to the backup set manually. Once backed up, thanks to the “True Archiving” approach of iDrive, all files from the external drive will remain backed up as long as an active iDrive subscription is maintained (or until they are deleted manually).

    More details can be found at the iDrive support centre by clicking here.

    These popular providers mentioned above are just a small sample of the many cloud backup providers available, hopefully this information helps highlight that different backup providers treat external hard drive backups differently and you must be careful to make sure your understand the rules of the provider you choose.

    Backing up an External Hard Drive to a NAS System

    Another popular method for keeping any external hard drives backed-up is to make use of a NAS (Network Attached Storage) system. NAS devices usually can be specified to contain a large volume of storage and can be configured so that they can be accessed over a local or home network.

    Popular choices of NAS include Synology and QNAP, both of which can configured so that the NAS storage itself can also be backed-up (off-site) to a 3rd party cloud storage provider such as AWS S3 or Backblaze B2.

    If you do decide upon making use of a NAS system for keeping any external drives backed-up then be aware that you will need some backup software which supports making local backups to a NAS device. Also be aware that NAS devices can often have a high initial purchase cost so might not be the best solution for many!

    Backing up an External Hard Drive to 3rd Party Cloud Storage

    One of the best methods of ensuring a safe backup of your external hard drive is to use hybrid backup software which supports backing up to a 3rd party cloud storage provider of your own choosing (e.g. Dropbox, Backblaze B2, AWS S3, OneDrive etc.). This approach will produce a similar result as many of the cloud backup subscription services (mentioned earlier on) do, but with some additional advantages thanks to using your own cloud storage subscriptions.

    One of the biggest advantages of using this approach is that you can specify the retention period for an external hard drive to whatever you would like it to be, also, since you pay for the storage yourself, you can leave the backed up data from the external drive on the cloud for as long as you like. This is in contrast to some cloud backup service providers which might delete such backups after as little as 30 days!

    This hybrid approach is therefore a great way of making the best of both worlds, not only can you get your external drive backed-up both locally to a NAS device or off-site to the cloud, but still retain a large degree of control over how your data is handled and retained on either.

    Our Top 5 Choices for Backing-up External Drives

    Below is a list of backup products which we believe offer a good approach to backing up external hard drives either to the cloud or locally to other external drives and NAS devices.

    Remember, the rating given to each piece of software by ourselves is only a guide and that the software with the highest rating might not necessarily be the best for your own personal needs. With this in mind, please refer to our detailed reviews of each entry for more information on the software itself and how it might help with your individual backup requirements.

    1. Ashampoo Backup Pro 17

    Ashampoo Backup Pro 17 is a fully featured backup suite with a great set of features for performing secure cloud backups in addition to local file and system image backups. Support is included for advanced encryption and compression as well as a powerful scheduling engine allowing for a secure and reliable backup scheme to be implemented with ease.

    Multiple 3rd party cloud storage options are available (including OneDrive, Google Drive and Dropbox) meaning this software is ideal for backing up an external drive to a cloud provider of your own choosing and then setting retention policies by yourself (meaning, if you do disconnect your external drive for long periods of time this shouldn’t cause any issues).

    Backup Pro 17 is priced at $49.99, also be sure to check out the Ashampoo Deals page by using this link!

    Ashampoo best backup software logo

    2. Acronis Cyber Protect Home Office

    Acronis has become a market leader in the backup world in recent years and rightly so, with Cyber Protect Home Office they have continued to refine their flagship backup offering and it continues to impress!

    The core of this application is, of course, getting the necessary PC or Mac backed up quickly and securely and this is an area Acronis excels in. The addition of cloud storage in recent years has helped to extend this offering and has been done so in such a way that, so long as an Acronis cloud subscription is maintained, any backups taken form external drives can potentially be saved indefinitely, even if the drive itself is removed for long periods of time (customer retention periods can also be set within the storage limits of the cloud subscription).

    Acronis offer a 30 day free trial of Cyber Protect Home Office including a trial of their excellent cloud storage, click here to find out more!

    3. Crashplan for Small Business

    If you are seeking a cloud backup solution with unlimited cloud storage and file versioning then Crashplan is the way to go!

    In addition to the very generous storage and versioning quotas on offer, Crashplan also allows you to backup all of your external drives for no additional cost and will never delete any files if the drive is not plugged in regularly! This makes Crashplan an ideal solution for creative professionals and freelancers with lots of data on external drives to keep backed up!

    Pricing for Crashplan is a simple $10 per PC per month with no annoying upselling, you can start a 30 day free trial by clicking here!

    4. Arq Backup (Arq 7)

    Arq Backup is a cloud backup solution which places an emphasis on simplicity, security and value for money. All of the major cloud storage providers are supported including Amazon S3, Backblaze B2, Google Drive and Dropbox meaning you can backup your external drives to cloud providers of your choice and have full control over how this data is handled.

    Arq 7 is priced at one-off $49.99 per device, there is also an option to subscribe to their Arq Premium service which provides use of the backup software for up to 5 devices alongside 1TB of included cloud storage for only $5.99 / month!

    Arq offer a free 30 day trial available by clicking here

    5. SpiderOak One

    SpiderOak One is an impressive, privacy and security focused, cloud backup service. Despite being cloud only (no image backups supported) it does feature built-in file synchronisation, file sharing and historic file versioning, all of which are included on all accounts by default.

    With regards to backing up external hard drives, SpiderOak have a policy never to remove files when an external drive is unplugged. This means, as long as you keep your subscription active, SpiderOak is a great solution for backing up such drives, even if they are unplugged for long periods of time.

    Pricing is very reasonable starting from just $6 / month, especially given this pricing is for a set storage allocation (starting at 150GB) and allows an unlimited number of devices to be backed up on each account.

    SpiderOak offers a 21 day free trial of SpiderOak One click here to find out more!
    Looking for backup software?

    Are you looking for help and advice on choosing the best backup software for your PC or Mac? If so then be sure to check out our guide to choosing backup software which also contains a list of our favorite choices as tested here on!

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