This is a screenshot that shows how the values in the grid differ from the export

When receiving data from a backend, the igDataSource class recreates the data on the client as well. When creating date objects on the client though, the date is always created in local time, so this introduces a difference. Though the igGrid is formatting this data based on tne enableUTCDates property, the igGridExcelExporter takes the client data and export it to the Excel worksheet, so in the end we may see such variations as in your case.

Possible resolutions are:

• if enableUTCDates is set to false, then the igGrid will not format the client data and there will be no differences between dates displayed in igGrid and exported Excel worksheet.
• interfere the exporting process by attaching to the cellExporting event and either changing the value written to the cell, or applying Excel formula that will format the display
• keep the enableUTCdates property to true, and place an additional hidden column in igGrid that will display date as if enableUTCDates is false. This column will be exported in the worksheet instead of the original one.

I recommend going for the last approach and I will attach a sample demonstrating how to achieve it shortly.