Lots of people struggle with installing the agent – which is why we are working on improving the process, but until then, we hope you find this article helpful.

Outlined below are some scenarios and troubleshooting steps that we believe – if followed carefully – should remediate the installation issue(s) you're facing. Please bear in mind, it can take a few minutes for the internal system to show on your targets page. If, by the end of this article, you're still having trouble, then please get in touch and we'll enlist the help of our security team. 💪

Do you have enough licenses?

The internal system won't show if you don't have enough licenses to cover scanning the device (and any other active targets listed). If you're unsure about your current license count, then please head to the targets page, and hover over the circle on the far right – clicking on that button will show you what targets are consuming licenses, and when they'll be up for release (and can be used on new targets – more on that, here).

If you're out of licenses, then you can update your license count by following the instructions in this article.

Trial users: Please note that the trial entitles you to three licenses, which can be used to scan three targets (internal or external) as many times as you like for 30 days. Deleting the target will not release the license. If you have already used all three and would like to test the internal scanner, please get in touch with a member of the team via the chatbot.

Do you need to reboot your system?

Sounds simple – but sometimes turning your machine off and back on again, can do the trick.

Is your internal system connected to the internet?

The agent needs to be able to reach out to cloud.tenable.com on port 443 to return the results to the platform.

Is your linking command correct?

Double check your linking command with the installation wizard, or manual installation guide to ensure that there aren't any mistakes.

Remember you have to edit the Key and DeviceName

Does the command reflect your current operating system?

Windows Server 2008 SP2, 7, 8.1 10 (32-bit) ➡️ NessusAgent-8.3.1-Win32.msi
Windows Server 2008 SP2, Server 2008 R2 SP1, Server 2012, Server 2012 R2, Server 2016, Server 2019, 7, 8.1, and 10 (64-bit) ➡️ NessusAgent-8.3.1-x64.msi

Are you running the linking command in the right folder?

When running the linking command you must either be in the folder where nessuscli is installed, or specify that folder in the path.

For reference, the default locations are as follows:
MacOS: cd /Library/Nessus/run/sbin/
Windows: cd "C:\Program Files\Tenable\Nessus Agent\"
Linux: cd /opt/nessus_agent/sbin/

For Windows, the commands would look something like this:
If you are in the folder where nessuscli is installed:

msiexec /i NessusAgent-8.2.4-x64.msi" NESSUS_SERVER="cloud.tenable.com:443" NESSUS_KEY=KEY NESSUS_NAME=Your Prefix_%computername% /qn

If you are specifying the path:

msiexec /i "[the path to where the installer was downloaded]\NessusAgent-8.2.4-x64.msi" NESSUS_SERVER="cloud.tenable.com:443" NESSUS_KEY=KEY NESSUS_NAME=Your Prefix_%computername% /qn

Was the original installation successful?

It sounds obvious but we often find that installation issues are typically related to accidental missteps, or unintentional typos. If you're not sure whether it was successful or not, try checking the agent status and recommended troubleshooting steps.

When using the installation wizard, did you opt for the installer or use the command in Step 3? (Windows only)

If you opted for the installer, rather than using the command highlighted above then you will need to unlink your agent and relink again.


In the terminal, as Admin, run the following command
nessuscli agent unlink

Check that the unlink command worked
Run the agent status, it should return:

Linked to: None
Link status: Not linked to a manager

Link the agent (again)

  1. Open the command terminal again – as Administrator

  2. Run the link command below
    (*Make sure you are in the right folder and have replaced DeviceName with your unique DeviceName)

    nessuscli agent link --host="cloud.tenable.com" --port="443" --key="819652a91d674e8d5be08e21299f1a3c69bd9806c72e24bc05df6b32b8db7fe1" --name="[DeviceName]"
  3. Check out targets page to see if it has appeared.

None of these applicable?

It's becoming more likely that you have an issue with your Anti Virus software, or an internet proxy/filter is getting in the way.

The best thing to do now, would be:

  • Pop a note in the chatbot confirming that you have read this article and eliminated all of the above

  • Send over a copy of your 'linking command'

  • Hang tight whilst the team investigate.

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