My subreport prints only one column when it should print more.

A subreport might print only one column if, in the subreport, Column Layout is set to Down, Then Across on the Columns tab in the Page Setup dialog box and, on the main report, the CanGrow property is set to Yes for the subreport control.

You can redesign the report in one of the following ways:

• In the subreport, change Column Layout to Across, Then Down and, on the main report, leave the CanGrow property set to Yes for the subreport control. The subreport control will display multiple columns and expand as needed.
  
  
• In the subreport, leave Column Layout set to Down, Then Across. On the main report, size the subreport control to fit the maximum number of records, and set its CanGrow property to No. Because the subreport control will always be the same size, if the number of records is greater than the maximum number you anticipated, records that don't fit in the subreport control will be truncated.

If possible, don't use a subreport. Put the controls that print the data in the main report in a group header or the page header, and put the controls that print the data in the subreport in the detail section.