On some systems, upgrading to Windows 10 Creators Update (version 1703) causes TinyTERM to come up to a blank screen, with no font display. It apparently connects and runs normally, but no text can be seen. This can affect applications other than TinyTERM as well.
When this happens, a registry change can fix this. You can download the registry edit file here. Or if you prefer to create the file yourself, create a text document with the .reg extension; e.g., FontFix.reg. Enter the following contents:
Windows Registry Editor Version 5.00
Either way, save the file to the affected PC. Close all running Windows applications, then double-click the file to execute it and make the change.
Once the registry edit finishes, reboot the PC. This step is crucial; otherwise, the fix will not be permanent. After the reboot, font display in TinyTERM will return to normal.