diff --git a/snikket_web/templates/admin_system.html b/snikket_web/templates/admin_system.html
index 00bcd35..fe547de 100644
--- a/snikket_web/templates/admin_system.html
+++ b/snikket_web/templates/admin_system.html
@@ -70,7 +70,7 @@
 		</dd>
 		<dt>{% trans %}Storage used by shared files{% endtrans %}</dt>
 		<dd>
-			{%- if metrics.prosody_uploads -%}
+			{%- if metrics.prosody_uploads | default(None) is not none -%}
 			{{ metrics.prosody_uploads | format_bytes }}
 			{%- else -%}
 			<em>{% trans %}unknown{% endtrans %}</em>