diff --git a/runner.js b/runner.js
index ae4b0cd..c45e759 100644
--- a/runner.js
+++ b/runner.js
@@ -31,7 +31,8 @@ export function runTest(job, onLine) {
       sitespeedArgs.push('--browsertime.chrome.args', 'disable-gpu');
     }
 
-    const env = { ...process.env, DISPLAY: process.env.DISPLAY || ':99' };
+    // Do not force DISPLAY — sitespeed.io starts and manages its own Xvfb
+    const env = { ...process.env };
 
     let child;
 
diff --git a/start.sh b/start.sh
index 2150a7c..5a60ee7 100644
--- a/start.sh
+++ b/start.sh
@@ -8,10 +8,7 @@ fi
 
 echo "[start.sh] SITESPEED_BIN=${SITESPEED_BIN:-NOT FOUND}"
 
-# Start virtual framebuffer so Chrome/Firefox have a display to render into
-Xvfb :99 -ac -screen 0 1920x1080x24 +extension RANDR &
-export DISPLAY=:99
-
-sleep 1
+# Do NOT start Xvfb here — sitespeed.io starts its own Xvfb instance
+# per test run. Starting one here causes a conflict on :99 and breaks Chrome.
 
 exec node /app/app.js