diff --git a/experiment/measurer/coverage_utils.py b/experiment/measurer/coverage_utils.py
index 42ca57385..dd2f3bb76 100644
--- a/experiment/measurer/coverage_utils.py
+++ b/experiment/measurer/coverage_utils.py
@@ -142,7 +142,7 @@ def generate_coverage_summary_json(self):
                                        self.merged_profdata_file,
                                        self.merged_summary_json_file,
                                        summary_only=False)
-        if result.retcode != 0:
+        if result is None or result.retcode != 0:
             logger.error(
                 'Merged coverage summary json file generation failed for '
                 f'fuzzer: {self.fuzzer},benchmark: {self.benchmark}.')
@@ -276,6 +276,10 @@ def generate_json_summary(coverage_binary,
 
     if summary_only:
         command.append('-summary-only')
+    if not os.path.exists(output_file):
+        logger.error(
+            f'Coverage summary json file defective or missing: {output_file}')
+        return None
 
     with open(output_file, 'w', encoding='utf-8') as dst_file:
         result = new_process.execute(command,