Save existing report as new name, doesn't work?

I have a working report, and I wish to create a variant of it. I was having problems with execution, and I thought it was my modifications to the saved copy. I saved 1215_Schedule.rpt as 1215_Schedule_2.rpt and modified the second. After a while, I deleted the copy. I again saved 1215_Schedule.rpt (after verifying it works) as 1215_Schedule_2.rpt. Without making any changes to that saved copy, the report doesn't produce any records. I find this odd. What am I doing wrong, or how do I troubleshoot? The SQL queries are identical, and I can't find anything different anywhere except the results.

Please ignore/delete this post. The issue was with front-end data being passed to the report from another application, I am all set.