This message appears because accuRx Chain needs Microsoft .NET 4.6.1 or later to run. Microsoft .NET is a standard Windows package which Chain and other software on your computer requires to run. Practice PCs usually have this software installed, but sometimes it can be an old version that requires updating.
You can fix this by downloading the correct package from here:
If this is successful just make sure you restart the accuRx install by clicking on the green accuRx Chain icon on your desktop.
The link above failed, what now?
This is most likely related to the permissions of your user account on the PC. The best next step is to ask your Practice Manager or System Administrator to login to your PC using their windows account to try run it with higher windows admin privileges.
If neither of the above can resolve it please get in touch with your local IT provider to update the software for you.