diff --git a/server/server-config/src/main/kotlin/suwayomi/tachidesk/server/ServerConfig.kt b/server/server-config/src/main/kotlin/suwayomi/tachidesk/server/ServerConfig.kt
index c000da1c7..3bdb9abc1 100644
--- a/server/server-config/src/main/kotlin/suwayomi/tachidesk/server/ServerConfig.kt
+++ b/server/server-config/src/main/kotlin/suwayomi/tachidesk/server/ServerConfig.kt
@@ -304,7 +304,7 @@ class ServerConfig(
                 },
             ),
         readMigrated = { extensionStores.value },
-        setMigrated = { extensionStores.value = (extensionStores.value + it).distinct() },
+        setMigrated = { extensionStores.value = it?.distinct().orEmpty() },
         typeInfo =
             SettingsRegistry.PartialTypeInfo(
                 specificType = "List<String>",