Explanation: Tabular, Summary, or Matrix to Joined The existing report becomes the first block in the joined report, and the report type becomes the principle report type for the joined report. Joined report blocks are formatted as summary reports, so if you switch from a summary to a joined report, your groupings stay the same. If you switch from a matrix to a joined report, groupings are converted the same way as when you switch from a matrix to a summary report. The following items aren't supported in joined reports, and aren't converted: Bucket fields Cross filters The Rows to Display filter https://help.salesforce.com/htviewhelpdoc?id=reports_changing_format.htm&siteLang=en_US