Is ESXi Really Free? Let’s put it to the Test

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Is ESXi Really Free? Let’s put it to the Test

As you probably know, ESXi can be evaluated, fully unlocked, for up to 60 days. Great news, if your short-term plan is to learn about VMware’s hypervisor and its entire feature set without spending a dime. There’s also option 2. ESXi can be used indefinitely, without cost by applying for a free license. So yes, technically and on paper, VMware ESXi is free to use. But, really, there’s no such thing as a free lunch and ESXi is no exception. Free ESXi license comes with a few restrictions which you should definitely know about. Now, as hard as I tried, I struggled to find anything solid on the subject save for this paragraph reproduced from this whitepaper.

VMware vSphere Hypervisor VMware vSphere Hypervisor is a free product that provides a simple and easy way to get started with virtualization at no cost. vSphere Hypervisor provides only basic virtualization capabilities, allowing customers to virtualize servers and run applications in virtual machines in a matter of minutes. vSphere Hypervisor cannot connect to vCenter Server and therefore cannot be centrally managed. Users can remotely manage individual vSphere Hypervisor hosts using the vSphere Client. There are no restrictions on the number of cores per physical CPU, on the number of physical CPUs per host and on the amount of RAM per server/ host. The maximum vCPUs per virtual machine is eight.”

A few blogs and user posts also mention other restrictions. Of particular interest, is the assertion that backup software will fail to connect to a free licensed ESXi host. The fact that I work at Altaro, a software company that writes great VMware and Hyper-V backup software, was enough of a compelling reason to try this out.

So, today I’ve tasked myself with testing these restrictions to verify once and for all, whether they hold true or not.



How to download ESXi and get a free license

Step 1 – Browse to this link and create an account if you don’t have one. If you do, sign in and proceed to the download area.

VMware sign-up page

Figure 1 – VMware sign-up page


Step 2 – Click on the Manually Download button to download the ESXi ISO image as shown in Fig.2 . Also, make sure to note down the license key listed under License Information (Fig. 2-2).

Note: At the time of writing, 6.5.0.d is the most recent update. For some reason, you can only download earlier releases which, for the purpose of this post, happens to be 6.5.0 a.

ESXi ISO file download and license information page

Figure 2 – ESXi ISO file download and license information page

Any ISO file differences?

Out of curiosity, I downloaded the ESXi 6.5.0a ISO from the evaluation center page just to compare it to the one downloaded from the free hypervisor link given above. As I thought, the 2 ISO files are identical. The file checksums from Fig. 2 above, match those listed in Fig. 3. Interestingly, the description for the ISO file is slightly different but I’m probably being somewhat paranoid.

ESXi ISO file download

Figure 3 – ESXi ISO file download and license information page (from the eval page)

Since I can’t help it, I renamed one of the ISO files, since they both have the same filename, and compared them at the byte level using Windows’ fc tool. As shown next, both files are 100% identical. That’s one case I can call closed.

Comparing 2 ESXi ISO files using a file comparison tool

Figure 4 – Comparing 2 ESXi ISO files using a file comparison tool

How to Apply a free ESXi license

I installed two nested ESXi instances using the ISO images just downloaded. Yes, I know. I already established that both ISO images are identical. Still, there’s no harm in trying.

ESXi Hypervisor is free for commercial use but includes a limited set of features. To use the hypervisor version, we need to register with our unique email ID. Once you have registered your email ID, download the hypervisor, and you can use a single license on up to 100 hosts.

Note: Have a look at Deploying vSphere ESXi 6.5 if you‘re new to installing ESXi.

Running two nested ESXi instances

Figure 5 – Running two nested ESXi instances; evaluation and free license

Once you’re done installing ESXi, use the host client to apply the license from the Manage -> Licensing tab. As per Fig.6, unless you apply the free license or one you’ve just purchased, the host will run in evaluation mode. The string of 0’s making up the license key is just that. An Enterprise Plus license that unlocks all vSphere features for you.

I installed VMware ESXi free on the 26-July-2016. The expiry date is set to 24-Sept-2016, 60 days to the date.

Assigning a license to ESXi via the host client

Figure 6 – Assigning a license to ESXi via the host client

Let’s see what happens when the free license is applied. Just click on the Assign License button and type or paste in the free license copied earlier from the download page.

Viewing ESXi free license details using the host client

Figure 7 – Viewing ESXi free license details using the host client

When the free license is applied, notice how the expiry date changes to Never, meaning the host is free to use indefinitely. One other thing you’ll notice is that the list of vSphere features is reduced to just one which in itself is not even a feature but rather a limitation; a maximum of 8 CPUs per VM.

Note: Use the vim-cmd vimsvc/license –show shell (SSH / shell to ESXi) command to determine which features are enabled. As expected, the command gives different results when run on a free licensed server and one running in evaluation mode.

The bulk of the features enabled in evaluation mode, such as vMotion, only take effect once the host is managed by vCenter. Since the free license does not allow you to add ESXi to vCenter, it’s only natural that these features are disabled since they cannot be used anyway. Well, that’s my train of thought but I could be wrong of course.

Viewing license information from the ESXi command line

Figure 8 – Viewing license information from the ESXi command line

Putting the ESXi free restrictions to the test

In this section, I will put the 3 restrictions to the test. As mentioned, I read so many conflicting posts that I had to try this out for myself. That said, I won’t be using a free license any time soon for production purposes. Still, there are people out there who apparently do, so it helps to know where you stand if you’re one of them.

Restriction 1 – A free licensed ESXi cannot be managed with vCenter Server

To test this first restriction of the free version of ESXi, I used PowerCLI to add a free licensed ESXi host to vCenter Server. I chose the PowerCLI method since any error or warning returned will clearly indicate if the task failed or not. The alternative would be to comb through a number of log files on vCenter, or ESXi, to figure out what’s going on in the free version.

Add-VMhost -user root -Password 1qaz!QAZ -Location (Get-Datacenter) -force

Result: The error returned confirms that a free licensed ESXi host cannot be managed by vCenter Server. The dead giveaway is the “License not available to perform the operation” included in the error message reproduced below.

add-vmhost : 26/07/2017 16:55:41 Add-VMHost The operation for the entity “host” failed with the following message: “License not available to perform the operation.”.

The VMware vSphere 6 Hypervisor license for Host does not include vCenter agent for VMware host. Upgrade the license.

At line:1 char:1

+ add-vmhost -user root -Password 1qaz!QAZ -Location (Ge …

+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

+ CategoryInfo : NotSpecified: (:) [Add-VMHost], NotEnoughLicenses

+ FullyQualifiedErrorId : Client20_TaskServiceImpl_CheckServerSideTaskUpdates_OperationFailed,VMware.VimAutomation.ViCore.Cmdlets.Commands.AddVMHost

Restriction 2 – A VM hosted on free ESXi is limited to 8 vCPUs at most

To test the second restriction of the free version of ESXi, I tried to create a VM with 10 CPUs i.e. one that exceeds the 8 vCPU limit.

Result: Using the Create VM wizard, you can still create a VM with the number of CPUs exceeding 8. However, it is not possible to power up the VM as can be seen next.

Attempting to run a VM with 10 CPUs fails on a free licensed ESXi

Figure 9 – Attempting to run a VM with 10 CPUs fails on a free licensed ESXi

In this example, I configured the VM with 10 sockets and 1 core each. Powering the VM will fail as well if, say, you set the VM to run with 5 CPU sockets, 2 cores each. Ultimately, the restriction imposed is on the number of logical processors.

Restriction 3 – VMs hosted on free ESXi cannot be backed up via the vSphere API

To test the final restriction, I used the Altaro Backup software to backup a VM hosted on free ESXi.

Result: Surely enough, the product detects that ESXi is running a free license and fails, or rather aborts, to connect as shown next.

VMs hosted on an ESXi host with a free license

Figure 10 – Altaro Backup, like many others, will not back up VMs hosted on an ESXi host with a free license

Besides these ESXi free license restrictions, I also tested mundane tasks such as taking snapshots, creating VMs, concurrent VM power ups, PowerCLI calls and what not. Unless I missed something, everything else seems to work like a charm.

Still, you won’t be able to backup your VMs, at least not with products that back up via the vSphere API. This restriction, in my opinion, is the biggest drawback for any admin. Perhaps, free ESXi could meet the business needs of very small businesses but for anything else properly licensed hosts is the way to go if scalability, advanced features and business continuity are in your pipeline.


To summarize, ESXi can be used for free and indefinitely once you apply a free ESXi license. There are at least 3 major restrictions which hinder the adoption of free ESXi other than for testing purposes or small shops.

These restrictions include:

    • The inability to manage a host equipped with a free ESXi license via vCenter
    • A limit of 8 vCPUs per VMs
    • Zero support for backup software meaning no VM backups or restores.

With that in mind, considering deploying free ESXi only as a last resort. An interim compromise would be to run ESXi in evaluation mode for 60 days. This unlocks all Enterprise Plus features but bear in mind that you must still purchase and apply a valid vSphere license once the trial period expires.

Altaro VM Backup
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Frequently Asked Questions

If the license expires and the host is managed by a vCenter server, it will be disconnected from it and you can’t change settings anymore. The virtual machines will continue running, however, be aware that you cannot power them on should they be powered off.
The evaluation license cannot be extended and should be replaced by a valid license. There is a trick to reset the evaluation period by deleted license.cfg but it goes against the EULA you accepted when installing vSphere.
The free version of ESXi includes the hypervisor itself only. It has a few limitations compared to the paid version such as a max of 8 vCPUs per VM, impossibility to manage it with a vCenter (no HA, DRS…), no support from GSS and others.
The vSphere licensing changed in March of 2020 to align with industry standard pricing models which are swiftly moving to core-based pricing. The licensing model is still based on sockets with a cap of 32 cores per license. For instance, a host equipped with 1 x 48 cores CPU will need 2 licenses (32 < 48 <64). Or a host with 2 sockets of 32 cores each will also require 2 licenses. This licensing model makes CPUs with more than 32 cores less financially attractive than before on a $/core basis.
There is no limit in the number of VMs that can run on ESXi with a free hypervisor license.
vSphere ESXi can indeed be used for free by getting a free license on

45 thoughts on "Is ESXi Really Free? Let’s put it to the Test"

  • Jason Fenech says:

    Interesting article.


  • Darren Pearce says:

    I have a customer with a fully licensed setup of ESXI, I would like to move the virtual server files back to my office to modify on our development servers and then once complete, move them back to the customer and replace the original virtual server files with the new ones.

    Would I need any licensing other than the free version, although the 60 day trial may be enough for this project, it may be useful if in the future we have the same scenario.

    • Jason Fenech says:


      Not sure what you mean by virtual server files? VMS perhaps? Regardless, with the 60 day evaluation versions of both ESXi and vCenter you should be able to move VMs across different hosts without any issues more so on the licensing side of things.

      Hope this helps.


  • Breno Carvalho says:

    Great article!

  • Ash says:

    I have been using FREE ESXI for past 1year. Recently i had an issue where my VM was not booting fine and it was just greyed out. I was then wondering is it possible to get a support for this machine? Is there any support contract available for FREE ESXI?

  • LeWayne Howg says:

    Have you come across any limitations with the free converter (converts physical machine to virtual guest) in conjunction with the free ESXi?

  • Erick L Gonzalez says:

    Jason, thank you for this post. It was very clear and informative – exactly what I was looking for.

    I would like to see one last section added to this post where you suggest alternatives (for the new devs out there).

  • Amrit N. Thakur says:

    Thanks Jason !!
    its really helpful for me.

    thank you once again

  • Joe B says:

    Thank you so much for this blog post, I couldn’t find ANY info on what the restrictions actually were.

  • Milan Rai says:

    Hi, Mr Jason,

    I was really looking for this kind of articles for VMWare vSphere Hypervisor and thank you so much for this.

    I want to purchase the vSphere Licence and in this regard, I’m looking forward that how to purchase in India.

  • John Smitty says:

    What are, if any, the workarounds or comparable options/suggestions towards getting around these limitations. For instance, what other backup options might you recommended, or what other management tools can be used, etc. These limitations will force users to engage in alternative (less efficient) approaches to achieve similar functionality, what are they?

    • Luke Orellana says:

      I believe Hyper-V’s free version provides more functionality. I’ve seen small companies go that route.

  • Meh says:

    RHEL or Debian oVirt

    There’s also Proxmox… a more techy solution, build it yourself!

    Essentially all the solutions even the paid ones are based on open source technology, with the exception of Microsoft and IBM.

    Might as well just build it yourself.

    • Luke Orellana says:

      Sounds like a great learning exercise. But, the problem with building it yourself for a small business, now you have to support it for the rest of its life 🙁

  • Christopher Anderson says:

    Here is a list of whats lost downgrading from trial to free .

    License downgrade: XXXX-XXXXX-XXXXX-XXXXX-XXXXX removes the following features: appha, autodeploy, bigdataex, contentlib, das, dpvmotion, dr, drs, dvs, encryptedvmotion, endpoint, esxHost, ft:8, h264remote, hostprofile, hotplug, metrovmotion, mpio, pmem, predictivedrs, proactiveha, rem, replication, serialuri:2, sioshares, smartcard, spbm, sriov, storageawarenessapi, storagedrs, svmotion, vaai, vflash, vgpu, viewaccel, vimapi, vmcrypt, vmotion, vshield, vstorage, vvolumes, xswitchvmotion, xvcvmotion


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