diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/task/FetchTask.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/task/FetchTask.java
index 5e7c58622..772956872 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/task/FetchTask.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/task/FetchTask.java
@@ -297,6 +297,7 @@ public abstract class FetchTask<T> extends Task<T> {
     }
 
     public static void setDownloadExecutorConcurrency(int concurrency) {
+        concurrency = Math.max(concurrency, 1);
         synchronized (Schedulers.class) {
             downloadExecutorConcurrency = concurrency;
             if (DOWNLOAD_EXECUTOR != null) {