Error Saving Credentials - Could not Load File or Assembly 'Newtonsoft Json Version='

Michael Barrow -

The issue

We have noticed on a number of practices the following error is being displayed upon logging into Pyrusium. This is usually when selecting a service, for example "Humber Coast and Vale".



The Cause

This is due to the configuration file for Pyrusium being changed by your IT Services. At the moment we have only noted this on NECS practices as setup on the NECS workstations is completed a little different. To ensure that the configuration is correct on NECS Practices, NECS use a template file, this file is correct for users using version of Pyrusium but for users using the above error will be displayed



  • To start browse to C:\Program Files (x86)\Black Pear Software\Pyrusium
  • Within this folder you should see a file called Pyrusium.exe.config, right click on the file and goto Open With-> Notepad. In some cases Notepad will not be displayed to which you will be required to click on Choose another app. Once done Notepad should be displayed in the list.
  • With the file open look for the section that states the following:-

<bindingRedirect oldVersion="" newVersion="" />

          If using version of Pyrusium this should be as follows:-

<bindingRedirect oldVersion="" newVersion="" />

  • Update the file and save
  • Now test Pyrusium, you should now find that all works without issues

**Note: In some cases updating files within executable folders requires Administrator permissions that can be obtained from your IT Services team.**


Should you require any further assistance please do not hesitate to contact Black Pear Support on


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