diff --git a/src/lyxfind.cpp b/src/lyxfind.cpp
index 5ceb345e60..c4b6b96a13 100644
--- a/src/lyxfind.cpp
+++ b/src/lyxfind.cpp
@@ -1060,7 +1060,7 @@ private:
 	int close_wildcards;
 public:
 	// Are we searching with regular expressions ?
-	bool use_regexp;
+	bool use_regexp = false;
 	static int valid_matches;
 	static vector <string> matches;
 	void FillResults(MatchResult &found_mr);