--- a/toolkit/crashreporter/nsExceptionHandler.cpp
+++ b/toolkit/crashreporter/nsExceptionHandler.cpp
@@ -2429,19 +2429,19 @@ CheckForLastRunCrash()
   // Ugly but effective.
   nsDependentString lastMinidump(
       reinterpret_cast<const PRUnichar*>(lastMinidump_contents.get()));
 #else
   nsAutoCString lastMinidump = lastMinidump_contents;
 #endif
   nsCOMPtr<nsIFile> lastMinidumpFile;
   CreateFileFromPath(lastMinidump.get(),
-                      getter_AddRefs(lastMinidumpFile));
-
-  if (NS_FAILED(lastMinidumpFile->Exists(&exists)) || !exists) {
+                     getter_AddRefs(lastMinidumpFile));
+
+  if (!lastMinidumpFile || NS_FAILED(lastMinidumpFile->Exists(&exists)) || !exists) {
     return false;
   }
 
   nsCOMPtr<nsIFile> lastExtraFile;
   if (!GetExtraFileForMinidump(lastMinidumpFile,
                                getter_AddRefs(lastExtraFile))) {
     return false;
   }