diff --git a/lib/media/media_source_engine.js b/lib/media/media_source_engine.js
index a5857a5d93..f1577bc591 100644
--- a/lib/media/media_source_engine.js
+++ b/lib/media/media_source_engine.js
@@ -392,7 +392,22 @@ shaka.media.MediaSourceEngine = class {
           }
         }
         const type = mimeType + this.config_.sourceBufferExtraFeatures;
-        const sourceBuffer = this.mediaSource_.addSourceBuffer(type);
+
+        this.destroyer_.ensureNotDestroyed();
+
+        let sourceBuffer;
+
+        try {
+          sourceBuffer = this.mediaSource_.addSourceBuffer(type);
+        } catch (exception) {
+          throw new shaka.util.Error(
+              shaka.util.Error.Severity.CRITICAL,
+              shaka.util.Error.Category.MEDIA,
+              shaka.util.Error.Code.MEDIA_SOURCE_OPERATION_THREW,
+              exception,
+              'The mediaSource_ status was' + this.mediaSource_.readyState +
+              'expected \'open\'');
+        }
 
         if (sequenceMode && !streamsByType.has(ContentType.TEXT)) {
           // There's no text stream, so we can set sequence mode early instead
diff --git a/package.json b/package.json
index a087a2782f..f3b01e3104 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@loomhq/shaka-player",
   "description": "DASH/EME video player library",
-  "version": "4.3.4-segments-17",
+  "version": "4.3.4-loomfork-20240327",
   "homepage": "https://github.com/shaka-project/shaka-player",
   "author": "Google",
   "maintainers": [
@@ -47,8 +47,6 @@
     "karma-spec-reporter": "^0.0.34",
     "karma-webdriver-launcher": "^1.0.8",
     "lcevc_dil.js": "^1.1.20",
-    "less": "https://gitpkg.now.sh/joeyparrish/less.js/packages/less?28c63a43",
-    "less-plugin-clean-css": "github:austingardner/less-plugin-clean-css#4e9e77bf",
     "material-design-lite": "^1.3.0",
     "mux.js": "^6.2.0",
     "open-sans-fonts": "^1.6.2",