diff --git a/src/renderer/main.ts b/src/renderer/main.ts
index 152369c..df6c69d 100644
--- a/src/renderer/main.ts
+++ b/src/renderer/main.ts
@@ -367,10 +367,14 @@ async function init(): Promise<void> {
     let streamTimeout = await db.getSetting<number>('streamTimeout', -1);
     let mcpTimeout = await db.getSetting<number>('mcpTimeout', -1);
 
-    // 兼容旧版：旧版把"未设置"存为0，新版0=禁用。将0迁移为-1(默认)
-    if (httpTimeout === 0) { httpTimeout = -1; await db.saveSetting('httpTimeout', -1); }
-    if (streamTimeout === 0) { streamTimeout = -1; await db.saveSetting('streamTimeout', -1); }
-    if (mcpTimeout === 0) { mcpTimeout = -1; await db.saveSetting('mcpTimeout', -1); }
+    // 兼容旧版：首次升级时，旧版把"未设置"存为0，一次性迁移为-1
+    const migrated = await db.getSetting<boolean>('_timeout_v2_migrated', false);
+    if (!migrated) {
+      if (httpTimeout === 0) { httpTimeout = -1; await db.saveSetting('httpTimeout', -1); }
+      if (streamTimeout === 0) { streamTimeout = -1; await db.saveSetting('streamTimeout', -1); }
+      if (mcpTimeout === 0) { mcpTimeout = -1; await db.saveSetting('mcpTimeout', -1); }
+      await db.saveSetting('_timeout_v2_migrated', true);
+    }
 
     // 应用流式超时到 state（agent-engine 读取，0=禁用）
     state.set('streamTimeout', streamTimeout >= 0 ? streamTimeout * 1000 : 300_000);