diff --git a/src/Entity/LogSystem/DBElement.php b/src/Entity/LogSystem/DBElement.php
deleted file mode 100644
index a4041585..00000000
--- a/src/Entity/LogSystem/DBElement.php
+++ /dev/null
@@ -1,28 +0,0 @@
-<?php
-/**
- * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
- *
- * Copyright (C) 2019 - 2020 Jan Böhmer (https://github.com/jbtronics)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
- */
-
-namespace App\Entity\LogSystem;
-
-
-class DBElement
-{
-
-}
\ No newline at end of file
diff --git a/src/Entity/LogSystem/DatabaseUpdatedLogEntry.php b/src/Entity/LogSystem/DatabaseUpdatedLogEntry.php
index 9d0dde59..4d9139df 100644
--- a/src/Entity/LogSystem/DatabaseUpdatedLogEntry.php
+++ b/src/Entity/LogSystem/DatabaseUpdatedLogEntry.php
@@ -58,7 +58,7 @@ class DatabaseUpdatedLogEntry extends AbstractLogEntry
      */
     public function getOldVersion(): string
     {
-        return (string) $this->extra['o'];
+        return (string) ($this->extra['o'] ?? '');
     }
 
     /**
@@ -68,6 +68,6 @@ class DatabaseUpdatedLogEntry extends AbstractLogEntry
      */
     public function getNewVersion(): string
     {
-        return (string) $this->extra['n'];
+        return (string) ($this->extra['n'] ?? '');
     }
 }
diff --git a/src/Entity/LogSystem/ElementDeletedLogEntry.php b/src/Entity/LogSystem/ElementDeletedLogEntry.php
index 53c59c42..9b8a0008 100644
--- a/src/Entity/LogSystem/ElementDeletedLogEntry.php
+++ b/src/Entity/LogSystem/ElementDeletedLogEntry.php
@@ -61,8 +61,8 @@ class ElementDeletedLogEntry extends AbstractLogEntry
         return $this;
     }
 
-    public function getOldName(): string
+    public function getOldName(): ?string
     {
-        return $this->extra['n'];
+        return $this->extra['n'] ?? null;
     }
 }
diff --git a/src/Entity/LogSystem/ExceptionLogEntry.php b/src/Entity/LogSystem/ExceptionLogEntry.php
index 5b36913f..74c35a64 100644
--- a/src/Entity/LogSystem/ExceptionLogEntry.php
+++ b/src/Entity/LogSystem/ExceptionLogEntry.php
@@ -57,7 +57,7 @@ class ExceptionLogEntry extends AbstractLogEntry
      */
     public function getFile(): string
     {
-        return $this->extra['f'];
+        return $this->extra['f'] ?? 'Unknown file';
     }
 
     /**
@@ -67,7 +67,7 @@ class ExceptionLogEntry extends AbstractLogEntry
      */
     public function getLine(): int
     {
-        return $this->extra['l'];
+        return $this->extra['l'] ?? -1;
     }
 
     /**
@@ -77,6 +77,6 @@ class ExceptionLogEntry extends AbstractLogEntry
      */
     public function getMessage(): string
     {
-        return $this->extra['m'];
+        return $this->extra['m'] ?? 'Unknown message';
     }
 }
diff --git a/src/Services/LogSystem/LogEntryExtraFormatter.php b/src/Services/LogSystem/LogEntryExtraFormatter.php
index c2993422..0141ac19 100644
--- a/src/Services/LogSystem/LogEntryExtraFormatter.php
+++ b/src/Services/LogSystem/LogEntryExtraFormatter.php
@@ -110,7 +110,7 @@ class LogEntryExtraFormatter
             return sprintf(
                 '<i>%s</i>: %s',
                 $this->translator->trans('log.element_deleted.old_name'),
-                $context->getOldName()
+                $context->getOldName() ?? $this->translator->trans('log.element_deleted.old_name.unknown')
             );
         }