diff --git a/src/mathed/MathParser.cpp b/src/mathed/MathParser.cpp
index 65ef72300b..0286ba103c 100644
--- a/src/mathed/MathParser.cpp
+++ b/src/mathed/MathParser.cpp
@@ -947,7 +947,9 @@ bool Parser::parse1(InsetMathGrid & grid, unsigned flags,
 			// do not create a BraceInset if they were written by LyX
 			// this helps to keep the annoyance of  "a choose b"  to a minimum
 			// But create a BraceInset if a script follows (#9348)
-			InsetMathBrace const * mb = ar[0]->asBraceInset();
+			InsetMathBrace const * mb;
+			if (ar.size() > 0)
+				mb = ar[0]->asBraceInset();
 			if (ar.size() == 1 && (ar[0]->extraBraces()
 			                       || (mb && mb->cell(0).size()
 			                           && !mb->cell(0)[0].nucleus()->asScriptInset())))