diff --git a/lib/Exif.php b/lib/Exif.php
index 705b9779..c1189861 100644
--- a/lib/Exif.php
+++ b/lib/Exif.php
@@ -202,14 +202,15 @@ class Exif
         }
 
         // Fall back to modification time
-        try {
-            $parseTz = new \DateTimeZone(getenv('TZ')); // debian
-        } catch (\Error $e) {
-            $parseTz = new \DateTimeZone('UTC');
-        }
+        $dt = new \DateTime('@'.$file->getMtime());
 
-        $dt = new \DateTime('@'.$file->getMtime(), $parseTz);
-        $dt->setTimezone($parseTz);
+        // Set timezone to system timezone
+        $tz = getenv('TZ') ?: date_default_timezone_get();
+        try {
+            $dt->setTimezone(new \DateTimeZone($tz));
+        } catch (\Exception $e) {
+            throw new \Error("FATAL: system timezone is invalid (TZ): $tz");
+        }
 
         return self::forgetTimezone($dt);
     }
diff --git a/src/components/Metadata.vue b/src/components/Metadata.vue
index 0993c352..29bcd829 100644
--- a/src/components/Metadata.vue
+++ b/src/components/Metadata.vue
@@ -179,8 +179,14 @@ export default defineComponent({
 
         let dateWithTz: DateTime | undefined = undefined;
 
+        // If no timezone info is available, we will show the local time only
+        // In this case, everything happens in UTC
+        if (!tzOffset && !tzId) {
+          dateWithTz = date.setZone('UTC');
+        }
+
         // Use timezone offset if available
-        if (tzOffset) {
+        if (!dateWithTz?.isValid && tzOffset) {
           dateWithTz = date.setZone('UTC' + tzOffset);
         }