diff --git a/funcext/TSOffice/worksheet/xlsxStyles.tsf b/funcext/TSOffice/worksheet/xlsxStyles.tsf
index 6112101..c50b1e2 100644
--- a/funcext/TSOffice/worksheet/xlsxStyles.tsf
+++ b/funcext/TSOffice/worksheet/xlsxStyles.tsf
@@ -177,7 +177,7 @@ Type xlsxStyles = Class
 		else begin
 			if ifstring(value) then
 			begin
-				if trystrtodatetime(value, r) or trystrtodate(value, r) then return array('n', r);		
+				if (pos("-", value) or pos("/", value)) and (trystrtodatetime(value, r) or trystrtodate(value, r)) then return array('n', r);
 				if trystrtofloat(value, r) then return array("n", value);
 				return array("s", value);
 			end