diff --git a/renderer/app.js b/renderer/app.js
index b24fae4..b836840 100644
--- a/renderer/app.js
+++ b/renderer/app.js
@@ -1246,13 +1246,15 @@ function getSelectedJobLinks() {
 // --- Upload ---
 async function startUpload() {
   if (healthCheckRunning || uploading) return;
+  uploading = true; // set immediately to prevent double-click race
+  updateQueueActionButtons();
 
   const hosters = getSelectedHosters();
-  if (hosters.length === 0) { alert('Bitte mindestens einen Hoster auswählen.'); return; }
+  if (hosters.length === 0) { alert('Bitte mindestens einen Hoster auswählen.'); uploading = false; updateQueueActionButtons(); return; }
   if (queueJobs.length === 0 && selectedFiles.length > 0) buildQueuePreview();
 
   const jobsToStart = queueJobs.filter((job) => job.status === 'preview' || job.status === 'queued');
-  if (jobsToStart.length === 0) return;
+  if (jobsToStart.length === 0) { uploading = false; updateQueueActionButtons(); return; }
 
   // Auto health check — only check hosters that have jobs to start
   if (autoHealthCheckEnabled) {
@@ -1265,10 +1267,12 @@ async function startUpload() {
         const errors = rows.filter(r => r.status === 'error');
         if (errors.length > 0) {
           alert(`Auto-Check fehlgeschlagen:\n${errors.map(r => `${r.hoster}: ${r.message}`).join('\n')}\n\nUpload wurde nicht gestartet.`);
+          uploading = false; updateQueueActionButtons();
           return;
         }
       } catch (err) {
         alert(`Auto-Check fehlgeschlagen: ${err.message}\nUpload wurde nicht gestartet.`);
+        uploading = false; updateQueueActionButtons();
         return;
       } finally {
         healthCheckRunning = false;
@@ -1276,7 +1280,6 @@ async function startUpload() {
     }
   }
 
-  uploading = true;
   queueJobs.forEach(j => {
     if (j.status === 'preview') j.status = 'queued';
   });
@@ -1306,12 +1309,14 @@ async function startUpload() {
 
 async function startSelectedUpload() {
   if (healthCheckRunning || uploading) return;
+  uploading = true; // set immediately to prevent double-click race
+  updateQueueActionButtons();
 
   const hosters = getSelectedHosters();
-  if (hosters.length === 0) { alert('Bitte mindestens einen Hoster auswählen.'); return; }
+  if (hosters.length === 0) { alert('Bitte mindestens einen Hoster auswählen.'); uploading = false; updateQueueActionButtons(); return; }
 
   const jobsToStart = queueJobs.filter((job) => selectedJobIds.has(job.id) && (job.status === 'preview' || job.status === 'queued'));
-  if (jobsToStart.length === 0) return;
+  if (jobsToStart.length === 0) { uploading = false; updateQueueActionButtons(); return; }
 
   // Auto health check — only check hosters that have jobs to start
   if (autoHealthCheckEnabled) {
@@ -1324,10 +1329,12 @@ async function startSelectedUpload() {
         const errors = rows.filter(r => r.status === 'error');
         if (errors.length > 0) {
           alert(`Auto-Check fehlgeschlagen:\n${errors.map(r => `${r.hoster}: ${r.message}`).join('\n')}\n\nUpload wurde nicht gestartet.`);
+          uploading = false; updateQueueActionButtons();
           return;
         }
       } catch (err) {
         alert(`Auto-Check fehlgeschlagen: ${err.message}\nUpload wurde nicht gestartet.`);
+        uploading = false; updateQueueActionButtons();
         return;
       } finally {
         healthCheckRunning = false;
@@ -1335,7 +1342,6 @@ async function startSelectedUpload() {
     }
   }
 
-  uploading = true;
   jobsToStart.forEach(j => {
     if (j.status === 'preview') j.status = 'queued';
   });