Created Unassigned: Excel found unreadable content when Style.NumberFormat.Format = "MM/dd/yyyy HH:mm:ss.0000" [9357]

Excel found unreadable content when Style.NumberFormat.Format = "MM/dd/yyyy HH:mm:ss.0000"

Milliseconds using Style.NumberFormat.Format = "MM/dd/yyyy HH:mm:ss.000" works fine.

7 decimal places would be nice B-)

This could be an Excel issue or other limitation beyond the scope of ClosedXML. But, you may want to trap for it to prevent generating an XLSX file that Excel does not like.

//AJ

PS: ClosedXML is GREAT WORK!!!