diff --git a/src/components/settings/system-network-settings.tsx b/src/components/settings/system-network-settings.tsx
index 74a7ec0..c0b0fd1 100644
--- a/src/components/settings/system-network-settings.tsx
+++ b/src/components/settings/system-network-settings.tsx
@@ -33,6 +33,7 @@ import {
   closeAppUpdate,
   getCurrentAppVersion,
   installAppUpdate,
+  normalizeAppUpdateError,
   relaunchApp,
 } from "@/lib/updater"
 
@@ -45,6 +46,8 @@ function isAppLocale(value: string): value is AppLocale {
   return APP_LANGUAGE_VALUES.includes(value as AppLocale)
 }
 
+type UpdateAction = "check" | "install"
+
 export function SystemNetworkSettings() {
   const t = useTranslations("SystemSettings")
   const tLanguage = useTranslations("Language")
@@ -172,6 +175,31 @@ export function SystemNetworkSettings() {
     }
   }, [appLanguage, languageSettings.language, setLanguageSettings, t])
 
+  const formatUpdateError = useCallback(
+    (error: unknown, action: UpdateAction): string => {
+      const { kind, rawMessage } = normalizeAppUpdateError(error)
+
+      switch (kind) {
+        case "source_unreachable":
+          return t("updateErrors.sourceUnavailable")
+        case "network":
+          return t("updateErrors.network")
+        case "download_failed":
+          return t("updateErrors.downloadFailed")
+        case "install_failed":
+          return t("updateErrors.installFailed")
+        case "unknown":
+        default:
+          if (action === "install") {
+            return t("updateErrors.installFailed")
+          }
+          console.error("[Settings] updater unknown error:", rawMessage)
+          return t("updateErrors.unknown")
+      }
+    },
+    [t]
+  )
+
   const checkForUpdates = useCallback(async () => {
     setCheckingUpdate(true)
     setUpdateError(null)
@@ -194,13 +222,14 @@ export function SystemNetworkSettings() {
         await closeAppUpdate(previousUpdate)
       }
     } catch (err) {
-      const message = err instanceof Error ? err.message : String(err)
+      const message = formatUpdateError(err, "check")
       setUpdateError(message)
       toast.error(t("checkUpdateFailed", { message }))
+      console.error("[Settings] check app update failed:", err)
     } finally {
       setCheckingUpdate(false)
     }
-  }, [availableUpdate, t])
+  }, [availableUpdate, formatUpdateError, t])
 
   const installUpdate = useCallback(async () => {
     if (!availableUpdate) return
@@ -213,13 +242,14 @@ export function SystemNetworkSettings() {
       toast.success(t("installSuccess"))
       await relaunchApp()
     } catch (err) {
-      const message = err instanceof Error ? err.message : String(err)
+      const message = formatUpdateError(err, "install")
       setUpdateError(message)
       toast.error(t("installFailed", { message }))
+      console.error("[Settings] install app update failed:", err)
     } finally {
       setInstallingUpdate(false)
     }
-  }, [availableUpdate, t])
+  }, [availableUpdate, formatUpdateError, t])
 
   if (loading) {
     return (
@@ -393,24 +423,31 @@ export function SystemNetworkSettings() {
           )}
 
           <div className="flex flex-wrap items-center gap-2 justify-end">
-            <Button
-              size="sm"
-              variant="secondary"
-              onClick={checkForUpdates}
-              disabled={checkingUpdate || installingUpdate}
-            >
-              {checkingUpdate ? (
-                <>
-                  <Loader2 className="h-3.5 w-3.5 animate-spin" />
-                  {t("checking")}
-                </>
-              ) : (
-                <>
-                  <RefreshCw className="h-3.5 w-3.5" />
-                  {t("checkUpdate")}
-                </>
-              )}
-            </Button>
+            {checkingUpdate ? (
+              <Button
+                key="checking-update"
+                size="sm"
+                variant="secondary"
+                disabled
+                aria-busy="true"
+                className="w-[9.5rem] justify-center transition-none"
+              >
+                <Loader2 className="h-3.5 w-3.5 animate-spin" />
+                {t("checking")}
+              </Button>
+            ) : (
+              <Button
+                key="check-update"
+                size="sm"
+                variant="secondary"
+                onClick={checkForUpdates}
+                disabled={installingUpdate}
+                className="w-[9.5rem] justify-center transition-none"
+              >
+                <RefreshCw className="h-3.5 w-3.5" />
+                {t("checkUpdate")}
+              </Button>
+            )}
 
             {availableUpdate && (
               <Button
diff --git a/src/i18n/messages/en.json b/src/i18n/messages/en.json
index d4604ba..1693df8 100644
--- a/src/i18n/messages/en.json
+++ b/src/i18n/messages/en.json
@@ -112,7 +112,14 @@
     "alreadyLatest": "You're on the latest version",
     "checkUpdateFailed": "Failed to check for updates: {message}",
     "installSuccess": "Update installed. Relaunching app.",
-    "installFailed": "Update failed: {message}"
+    "installFailed": "Update failed: {message}",
+    "updateErrors": {
+      "sourceUnavailable": "Cannot reach the update source. Check your network or proxy and try again.",
+      "network": "Network connection failed. Check your network or proxy and try again.",
+      "downloadFailed": "Failed to download update package. Please try again later.",
+      "installFailed": "Failed to install update. Please close the app and try again.",
+      "unknown": "Update failed. Please try again later."
+    }
   },
   "ShortcutSettings": {
     "sectionTitle": "Shortcuts",
diff --git a/src/i18n/messages/zh-CN.json b/src/i18n/messages/zh-CN.json
index a9f40b6..c5d5efb 100644
--- a/src/i18n/messages/zh-CN.json
+++ b/src/i18n/messages/zh-CN.json
@@ -112,7 +112,14 @@
     "alreadyLatest": "当前已经是最新版本",
     "checkUpdateFailed": "检查更新失败：{message}",
     "installSuccess": "升级包已安装，正在重启应用",
-    "installFailed": "升级失败：{message}"
+    "installFailed": "升级失败：{message}",
+    "updateErrors": {
+      "sourceUnavailable": "无法连接更新源，请检查网络或代理设置后重试。",
+      "network": "网络连接异常，请检查网络或代理设置后重试。",
+      "downloadFailed": "下载更新包失败，请稍后重试。",
+      "installFailed": "安装更新失败，请关闭应用后重试。",
+      "unknown": "更新失败，请稍后重试。"
+    }
   },
   "ShortcutSettings": {
     "sectionTitle": "快捷键",
diff --git a/src/i18n/messages/zh-TW.json b/src/i18n/messages/zh-TW.json
index 53c6429..2ee9d73 100644
--- a/src/i18n/messages/zh-TW.json
+++ b/src/i18n/messages/zh-TW.json
@@ -112,7 +112,14 @@
     "alreadyLatest": "目前已是最新版本",
     "checkUpdateFailed": "檢查更新失敗：{message}",
     "installSuccess": "升級包已安裝，正在重新啟動應用",
-    "installFailed": "升級失敗：{message}"
+    "installFailed": "升級失敗：{message}",
+    "updateErrors": {
+      "sourceUnavailable": "無法連線更新來源，請檢查網路或代理設定後重試。",
+      "network": "網路連線異常，請檢查網路或代理設定後重試。",
+      "downloadFailed": "下載更新包失敗，請稍後再試。",
+      "installFailed": "安裝更新失敗，請關閉應用後重試。",
+      "unknown": "更新失敗，請稍後再試。"
+    }
   },
   "ShortcutSettings": {
     "sectionTitle": "快捷鍵",
diff --git a/src/lib/updater.ts b/src/lib/updater.ts
index 66b3aa7..b31f5db 100644
--- a/src/lib/updater.ts
+++ b/src/lib/updater.ts
@@ -7,6 +7,18 @@ export interface AppUpdateCheckResult {
   update: Update | null
 }
 
+export type AppUpdateErrorKind =
+  | "source_unreachable"
+  | "network"
+  | "download_failed"
+  | "install_failed"
+  | "unknown"
+
+export interface AppUpdateErrorInfo {
+  kind: AppUpdateErrorKind
+  rawMessage: string
+}
+
 export async function getCurrentAppVersion(): Promise<string> {
   return getVersion()
 }
@@ -27,3 +39,49 @@ export async function relaunchApp(): Promise<void> {
 export async function closeAppUpdate(update: Update): Promise<void> {
   await update.close()
 }
+
+function toErrorMessage(error: unknown): string {
+  if (error instanceof Error) return error.message
+  return String(error)
+}
+
+export function normalizeAppUpdateError(error: unknown): AppUpdateErrorInfo {
+  const rawMessage = toErrorMessage(error)
+  const normalized = rawMessage.toLowerCase()
+
+  if (
+    normalized.includes("latest.json") ||
+    normalized.includes("/releases/latest/download/")
+  ) {
+    return { kind: "source_unreachable", rawMessage }
+  }
+
+  if (
+    normalized.includes("error sending request for url") ||
+    normalized.includes("failed to send request") ||
+    normalized.includes("network") ||
+    normalized.includes("timed out") ||
+    normalized.includes("dns") ||
+    normalized.includes("connection refused")
+  ) {
+    return { kind: "network", rawMessage }
+  }
+
+  if (
+    normalized.includes("download") ||
+    normalized.includes("checksum") ||
+    normalized.includes("content-length")
+  ) {
+    return { kind: "download_failed", rawMessage }
+  }
+
+  if (
+    normalized.includes("install") ||
+    normalized.includes("installer") ||
+    normalized.includes("permission denied")
+  ) {
+    return { kind: "install_failed", rawMessage }
+  }
+
+  return { kind: "unknown", rawMessage }
+}