When the Secure Viewer Thin Client crashes upon startup, this is typically due to missing prerequisites. Usually a .NET prerequisite is missing. Verifying that .NET 3.5 and .NET 4.8 are installed, and installing them if not, is required.
Verify .NET 3.5 is installed by clicking Start and typing 'Turn Windows Features'. Then click 'Turn Windows Features On or Off'. Make sure .NET 3.5 is enabled. If it is not, enable it and then click OK.
The .NET 4.8 installer can be downloaded here: https://dotnet.microsoft.com/download/dotnet-framework/thank-you/net48-offline-installer
Once downloaded, run the installer. It will confirm if .NET 4.8 is already installed, and install it otherwise.
With .NET 3.5 and 4.8 installed, the Secure Viewer Thin Client should now launch without crashing upon startup. In case crashing persists, please contact InduSoft support for further assistance.