diff --git a/src/libs/utils/fileutils.cpp b/src/libs/utils/fileutils.cpp
index 48d87871002..0110857790c 100644
--- a/src/libs/utils/fileutils.cpp
+++ b/src/libs/utils/fileutils.cpp
@@ -631,6 +631,7 @@ FileName FileName::parentDir() const
 
     const QString path = basePath + QLatin1String("/..");
     const QString parent = QDir::cleanPath(path);
+    QTC_ASSERT(parent != path, return FileName());
 
     return FileName::fromString(parent);
 }