diff --git a/CLTool/src/tc.cpp b/CLTool/src/tc.cpp
index e79e66d..ae1418f 100644
--- a/CLTool/src/tc.cpp
+++ b/CLTool/src/tc.cpp
@@ -100,6 +100,11 @@ void ExtractBasename(const char *filename, char *buf, size_t bufSz) {
     }
   }
 
+  if(!base) {
+    fprintf(stderr, "Filename (%s) has no extension, we don't know how to deal with it!\n", filename);
+    exit(1);
+  }
+
   size_t numChars = ext - base + 1;
   size_t toCopy = ::std::min(numChars, bufSz);
   memcpy(buf, base, toCopy);