diff --git a/engine/common/host.c b/engine/common/host.c
index 07fbfd55..9b0c6285 100644
--- a/engine/common/host.c
+++ b/engine/common/host.c
@@ -1008,7 +1008,7 @@ void Host_InitCommon( int argc, char **argv, const char *progname, qboolean bCha
 
 	len = Q_strlen( host.rootdir );
 
-	if( host.rootdir[len - 1] == '/' )
+	if( len && host.rootdir[len - 1] == '/' )
 		host.rootdir[len - 1] = 0;
 
 	// get readonly root. The order is: check for arg, then env.