diff --git a/dashboard/src/views/EmailMailboxesView.vue b/dashboard/src/views/EmailMailboxesView.vue
index 7ce6fb884..d4cc82765 100644
--- a/dashboard/src/views/EmailMailboxesView.vue
+++ b/dashboard/src/views/EmailMailboxesView.vue
@@ -39,10 +39,14 @@ const columns = {
   },
   usage: {
     label: t('email.incoming.mailboxes.usage'),
-    sort: true,
+    sort: (a, b) => {
+      if (!a.diskSize) return -1;
+      if (!b.diskSize) return 1;
+      return a.diskSize - b.diskSize;
+    },
     hideMobile: true,
   },
-  quota: {
+  storageQuota: {
     label: 'Quota',
     sort: true,
     hideMobile: true,
@@ -243,7 +247,7 @@ onMounted(async () => {
           <span v-if="mailbox.usage || mailbox.usage === 0">{{ prettyDecimalSize(mailbox.usage.diskSize)  }}</span>
           <span v-else>{{ $t('main.loadingPlaceholder') }} ...</span>
         </template>
-        <template #quota="mailbox">
+        <template #storageQuota="mailbox">
           <span v-if="mailbox.usage && mailbox.usage.quotaLimit">{{ prettyDecimalSize(mailbox.usage.quotaLimit) }}</span>
         </template>
         <template #actions="mailbox">