diff --git a/src/plugins/projectexplorer/customparserconfigdialog.cpp b/src/plugins/projectexplorer/customparserconfigdialog.cpp
index 5584ae480af..f67cd25b9d9 100644
--- a/src/plugins/projectexplorer/customparserconfigdialog.cpp
+++ b/src/plugins/projectexplorer/customparserconfigdialog.cpp
@@ -278,7 +278,8 @@ bool CustomParserConfigDialog::checkPattern(QLineEdit *pattern, const QString &o
     pattern->setPalette(palette);
     pattern->setToolTip(rx.isValid() ? QString() : rx.errorString());
 
-    *match = rx.match(outputText);
+    if (rx.isValid())
+        *match = rx.match(outputText);
     if (rx.pattern().isEmpty() || !rx.isValid() || !match->hasMatch()) {
         *errorMessage = QString::fromLatin1("<font color=\"%1\">%2 ").arg(
                     Utils::creatorTheme()->color(Utils::Theme::TextColorError).name(),