diff --git a/public/index.html b/public/index.html
index 257c68b..3468742 100644
--- a/public/index.html
+++ b/public/index.html
@@ -464,11 +464,12 @@ body::before{content:'';position:fixed;inset:0;background:radial-gradient(ellips
     <div style="margin-top:1.5rem;margin-bottom:1.25rem">
       <div style="display:flex;gap:.5rem;margin-bottom:.75rem">
         <button class="mode-btn active-http" id="btn-http" onclick="setMode('http')">🌐 HTTP Mode</button>
-        <button class="mode-btn" id="btn-udp" onclick="setMode('udp')">⚡ UDP Mode</button>
+        <button class="mode-btn" id="btn-udp" disabled style="opacity:.4;cursor:not-allowed;pointer-events:none">🖥️ Electron App</button>
       </div>
       <div class="mode-desc" id="mode-desc" style="margin-bottom:0">
         <strong id="mode-label">HTTP Mode:</strong> <span id="mode-detail">Parallel chunked HTTP upload (6 concurrent 32 MB parts). Aspera-class speed — no UDP needed.</span>
       </div>
+      <div style="text-align:right;margin-top:.3rem;font-size:.7rem;color:var(--text-dim);opacity:.6">Electron App — Aspera-speed desktop application (coming soon)</div>
     </div>
 
     <div style="margin-bottom:1.5rem">
diff --git a/server.js b/server.js
index c34727d..c64490f 100644
--- a/server.js
+++ b/server.js
@@ -455,22 +455,12 @@ app.post("/api/s3/test", requireAdmin, async (req, res) => {
     return res.status(400).json({ success: false, error: "Bucket, Access Key ID, and Secret Key are required to test" });
 
   const testClient = buildS3Client(testCfg);
-  const testKey = `_dragonwind_test_${Date.now()}.txt`;
 
   try {
-    // Upload a tiny test file
-    await testClient.send(new PutObjectCommand({
-      Bucket: testCfg.bucket,
-      Key: testKey,
-      Body: Buffer.from("Dragon Wind S3 connection test"),
-      ContentType: "text/plain",
-    }));
-    // Delete it immediately
-    try {
-      await testClient.send(new DeleteObjectCommand({ Bucket: testCfg.bucket, Key: testKey }));
-    } catch (_) { /* delete failure is non-fatal */ }
+    // Test by checking if bucket exists and is accessible
+    await testClient.send(new HeadBucketCommand({ Bucket: testCfg.bucket }));
 
-    res.json({ success: true, message: "S3 connection confirmed! Test file uploaded and deleted successfully." });
+    res.json({ success: true, message: "✓ S3 connection confirmed! Credentials are valid and the bucket is accessible." });
   } catch (err) {
     let friendly = err.message;
     if (err.name === "NoSuchBucket") friendly = `Bucket "${testCfg.bucket}" does not exist`;