When updating or installing SAP 2000 16.1 and you receive error 1722.
Make sure all windows updates are up to date. A key update is .NET Framework 4.5.1 (kb2858725).
To check if this update has been installed, when you open windows update
you will see Under the update status in blue "View update history".
If you click on this and then sort by name you can see if it has been installed.
You can also manually download and install the update from:
Run CCleaner and repair any registry errors.
Restart your computer.
Close ant program running in your task bar such as Bing Desktop.
Start the SAP update/install again.