I have a grid where the data is populated with a datatable. I'm using the FillWithData command to accomplish this "iGrid1.FillWithData(DT);". All works completely fine, grouping, formatting, etc. until I try to update the data. I use the FillWithData command to load updated data into the grid. The grid goes blank, however I know the datatable is loaded because when I use the iGPrintManager it prints the updated datatable data. Additionally the AutoFilterManager drop downs shows the updated column data.

Any suggestions?
H-m, we never faced such an issue. Can you prepare and send us a sample we can use to reproduce the problem?
I created a new form application with two data tables. I could fill the grid with the first data table then fill the grid with the second data table. In other words I could not duplicate the problem. So I started removing grid modifications in my application , formatting, grouping, and subtotaling. I found that the data table will refresh until the following command is issued.

iGSubtotalManager.ShowSubtotals(grid, new int[] { 1 });

When the data table is loaded the first time, with the showsubtotals, all is well. if I refill the grid with the second data table the grid goes blank.

Solution / workaround -- issue IGSubtoalManager.HideSubtotals(grid) prior to the second grid.FillWithData(DT).
Then I know where the problem is as we have discussed this issue recently with another customer: 

We've fixed the iGSubtotalManager class after that, and you can redownload it from the Extra Sample Lib to get the new fixed version.
Thank you for the update.