Troubleshooting the Desktop Connector

How to fix problems and errors with the desktop connector

Updated over a week ago

This article explains some of the common issues you may encounter while running the Fathom Desktop Connector, with accompanying resolutions.  We have a series of troubleshooting steps which may help to easily resolve the situation before you need to contact Fathom support at

Getting up to date

The first thing you should do is make sure you have the most recent version of the Desktop Connector installed. Usually the Desktop Connector will update itself automatically, but we have encountered corrupted installations in the past.

To do this please open your Windows File Explorer and delete this folder:

C:\Users\{your current username}\AppData\Local\Apps\2.0\

This will remove the current copy of the Desktop Connector. After doing this, please login to Fathom and download the latest version of the Desktop Connector again.

Starting the Desktop Connector

Once we are confident you are up to date, we can verify if the Desktop Connector is starting properly.

Security Warning

You may see an dialog similar to this, with the message, "Your administrator has blocked this application because ..."

This is a result of security settings either specific to your local PC or enforced by a group policy if you are in a corporate environment. Please try the following resolutions in order:

  1. Check that your PC/browser trusts the Digicert certificate

    A Digicert certificate is used to sign the desktop connector. You should first check that you have the correct root certificate installed. Go to this webpage and verify that no warning is presented.  

    If the root certificate turns out to be the issue then, if you are comfortable, you can use the following utility to repair the certificate chain.

  2. Ensure that the ClickOnce Trust Prompt behaviour is correct

    For advanced technical users, you can edit the Windows Registry to verify that the correct trust is assigned to Click Once applications (eg. The Fathom Desktop connector).

    This article helps demonstrate the changes required.

    For more information please see the following article from Microsoft.

  3. Add Fathom as a trusted site in your local internet settings.

    Open Windows Control Panel and go to Internet options (you can also access these settings by opening the Start menu, typing Internet options and pressing Enter).

    Click the Security tab and select the Trusted Sites zone.
    Click the Sites button on the right side and add the following URL's as shown below:

    Click OK to Save.

Exception and/or crash

An error may present itself that looks similar to this: 

In this case we need to find the error detail from the 'Event Viewer' in Windows. You can start the event viewer by going to 'Start' in Windows and typing 'Event'. Once it has started, go to 'Windows Logs > Application' to see if you can spot any error related to the Desktop Connector. Please copy and paste the detail from this error and send it to us. 

Instructions related to the Windows Event Viewer can be found at this website.

Error: 'Application Improperly Formatted'

This error is caused by not having the correct .NET Framework version installed. Due to a recent Microsoft update we now require that the computer running the Connector has the Microsoft .NET Framework v4.7.1 installed. Please see the instructions for installation in the requirements section.

Unable to Connect to Fathom servers due to SSL/TLS issue

The Fathom Desktop Connector communicates with Fathom via our API. When starting the Connector, some users may see an error indicating that it is unable to connect to Fathom and/or that the Internet may not be available.

You can test the Internet availability in a web browser. If you can reach other websites then the issue may be due to a TLS 1.0 issue.

TLS 1.0 is a security protocol, used by Windows operating systems, that was released in 1999 and was deprecated a couple of years ago. It has been replaced by more secure and modern protocols and current best practice is to use TLS 1.2. The Fathom API no longer supports TLS 1.0 as it is a known security risk.

You can find more information on TLS 1.0 here:

The root cause is often that older versions of Windows (eg. Windows 7, Windows Server 2008) have not been updated or patched to support the newer protocols.

Microsoft have an excellent article explaining the TLS 1.0 problem, which shows how different versions of Windows are affected.

Windows 7

To enable support for TLS 1.2 in Windows 7, Microsoft provides  a specific update. Note that a prerequisite for this update is Service Pack 1 and it requires editing the Windows Registry and a subsequent reboot.

If you are confident that your environment is already up to date, you can try following the instructions below:

Windows Server 2008

To add support for TLS 1.2 in Windows Server 2008, the following Windows update needs to be installed. Note that the update also requires an update to the Windows Registry.

Support Log

If the Desktop Connector starts properly and the problem occurs subsequent to this, it often helps diagnosis if you can send us the 'Support Log'.

Any other screenshots or detail that you can provide with regards to your environment or that you think may be helpful are also welcome. Send these through to

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