Be cautious of using the No Printer setting. With current updates to CR Designer and RPT files and the SDK using the no printer is not recommended now.
But do use the Dissociate feature, this will tell CR to use the same family type of printer and settings but not specifically rely on the one the report was Designed and saved with.
CR now saves the Printer name and Custom Paper Size name in the RPT so if/when you use the report in Enterprise the SDK will try to find that custom paper size name, by name and not by the ENUM assigned to the custom paper size.
As long as you update the reports manually to use a current valid printer and save them the same "family" of printers should work without issues.
When checking the No Printer option on CR still references you Default Printer to be able to set some default properties. So if your default printer is a Zebra Label printer and the report was designed for am 81/2 x 11 paper size this is going to cause problems...
Try to set the updated reports to a real valid printer now.
Don