diff --git a/slpkg/upgrade.py b/slpkg/upgrade.py
index b0999881..a0630ecf 100644
--- a/slpkg/upgrade.py
+++ b/slpkg/upgrade.py
@@ -145,7 +145,7 @@ class Upgrade(Configs):  # pylint: disable=[R0902]
         log[self.repository]: dict = {
             'installed package': installed,
             'repository package': self.data[name]['package'],
-            'error': err
+            'error': str(err)
         }
 
         self.upgrade_log_file.write_text(json.dumps(log, indent=4), encoding='utf-8')