diff --git a/src/client/app/admin/views/federation.vue b/src/client/app/admin/views/federation.vue
index 8b7719069..b419cca1d 100644
--- a/src/client/app/admin/views/federation.vue
+++ b/src/client/app/admin/views/federation.vue
@@ -509,7 +509,7 @@ export default Vue.extend({
 
 		saveBlockedHosts() {
 			this.$root.api('admin/update-meta', {
-				blockedHosts: this.blockedHosts.split('\n')
+				blockedHosts: this.blockedHosts ? this.blockedHosts.split('\n') : []
 			}).then(() => {
 				this.$root.dialog({
 					type: 'success',
diff --git a/src/client/app/admin/views/instance.vue b/src/client/app/admin/views/instance.vue
index 2d0fc9b40..223b3531e 100644
--- a/src/client/app/admin/views/instance.vue
+++ b/src/client/app/admin/views/instance.vue
@@ -461,7 +461,7 @@ export default Vue.extend({
 				iconUrl: this.iconUrl,
 				name: this.name,
 				description: this.description,
-				langs: this.languages.split(' '),
+				langs: this.languages ? this.languages.split(' ') : [],
 				cacheRemoteFiles: this.cacheRemoteFiles,
 				localDriveCapacityMb: parseInt(this.localDriveCapacityMb, 10),
 				remoteDriveCapacityMb: parseInt(this.remoteDriveCapacityMb, 10),
@@ -490,8 +490,8 @@ export default Vue.extend({
 				enableServiceWorker: this.enableServiceWorker,
 				swPublicKey: this.swPublicKey,
 				swPrivateKey: this.swPrivateKey,
-				pinnedUsers: this.pinnedUsers.split('\n'),
-				hiddenTags: this.hiddenTags.split('\n'),
+				pinnedUsers: this.pinnedUsers ? this.pinnedUsers.split('\n') : [],
+				hiddenTags: this.hiddenTags ? this.hiddenTags.split('\n') : [],
 				useObjectStorage: this.useObjectStorage,
 				objectStorageBaseUrl: this.objectStorageBaseUrl ? this.objectStorageBaseUrl : null,
 				objectStorageBucket: this.objectStorageBucket ? this.objectStorageBucket : null,
diff --git a/src/server/api/endpoints/admin/update-meta.ts b/src/server/api/endpoints/admin/update-meta.ts
index 834faa42b..1d6973e7a 100644
--- a/src/server/api/endpoints/admin/update-meta.ts
+++ b/src/server/api/endpoints/admin/update-meta.ts
@@ -430,15 +430,15 @@ export default define(meta, async (ps, me) => {
 	}
 
 	if (Array.isArray(ps.pinnedUsers)) {
-		set.pinnedUsers = ps.pinnedUsers;
+		set.pinnedUsers = ps.pinnedUsers.filter(Boolean);
 	}
 
 	if (Array.isArray(ps.hiddenTags)) {
-		set.hiddenTags = ps.hiddenTags;
+		set.hiddenTags = ps.hiddenTags.filter(Boolean);
 	}
 
 	if (Array.isArray(ps.blockedHosts)) {
-		set.blockedHosts = ps.blockedHosts;
+		set.blockedHosts = ps.blockedHosts.filter(Boolean);
 	}
 
 	if (ps.mascotImageUrl !== undefined) {
@@ -501,8 +501,8 @@ export default define(meta, async (ps, me) => {
 		set.maintainerEmail = ps.maintainerEmail;
 	}
 
-	if (ps.langs !== undefined) {
-		set.langs = ps.langs;
+	if (Array.isArray(ps.langs)) {
+		set.langs = ps.langs.filter(Boolean);
 	}
 
 	if (ps.summalyProxy !== undefined) {