This error is quite odd and we have not received such reports so far. I tried to reproduce the problem in our local tests by creating a simple test page, but my efforts were not successful – everything worked smoothly and the GroupRowInfoFormat property displays the caption and the value correctly. I bind WebGrid to Employees table of Northwind database using AccessDataSource control. The grouping feature in the grid is enabled and the GroupRowInfoFormatDefault property is set to “[caption] : [value]”.

I enclosed my test page as attachment. You may run and view the page in your local end and let us know if the problem is persist?

We are willing to advice you further but in order to do so we would need you to elaborate on your specific scenario and possibly give us a running simple sample that replicates the issue that we can use to observe the problematic behavior.