What have you tried? Can you print from other applications? What operating system? What version of Lightroom? Are there any error messages? I have the Canon Pixma Pro-100, using Lightroom CC 2015, and I have no problems printing from Lightroom or any other application. Please provide as many details as you can.
I have tried nearly everything. The printer works in other applications.
Error Messages vary from Printer Not Responding to Canon IJ Preview is in operation.
Operating System is Windows 10.
Lightroom CC 2015 - just downloaded two weeks ago from Adobe with the Creative Cloud Package.
I am using Windows 10 as well. If you go to page setup, are you able to choose the Canon Pixma Pro-100? Are you trying to print wireless or with direct connection? Have you tried unchecking the print preview option on the first tab of the printer driver setup to see if that makes a difference?