This is Microsoft Visual Studio issue:
https://social.msdn.microsoft.com/Forums/office/en-US/04a062a3-a748-45ce-8539-3d95ad1ac77c/in-visual-studio-2017-oninitdialog-isnt-called-for-a-a-class-derived-from-cprintdialog-if-the?forum=vcgeneral
The bug has fixes in Visual Studio 2017. TurboCAD is built by Visual Studio 2015.
Workaround:
Never use the "Microsoft Print to PDF" printer in TurboCAD and do not set this printer as system's default printer. Instead of it use other PDF printers.


You need to go to Control Panel/Devices and Printers. In the Printers dropdown, make sure your selected printer is not "Microsoft Print to PDF". If it's not and you are still facing issues, then switch your current printer to any other printer from the list. After doing this, you need to relaunch TurboCAD and check if the issue is resolved,