diff --git a/js/h5p-content-upgrade-process.js b/js/h5p-content-upgrade-process.js
index 6954622..cab1dfd 100644
--- a/js/h5p-content-upgrade-process.js
+++ b/js/h5p-content-upgrade-process.js
@@ -54,6 +54,12 @@ H5P.ContentUpgradeProcess = (function (Version) {
       if (err) {
         return done(err);
       }
+      if (library.semantics === null) {
+        return done({
+          type: 'libraryMissing',
+          library: library.name + ' ' + library.version.major + '.' + library.version.minor
+        });
+      }
 
       // Run upgrade routines on params
       self.processParams(library, oldVersion, newVersion, params, metadata, function (err, params, metadata) {
diff --git a/js/h5p-content-upgrade.js b/js/h5p-content-upgrade.js
index 168c694..9dc066c 100644
--- a/js/h5p-content-upgrade.js
+++ b/js/h5p-content-upgrade.js
@@ -422,6 +422,10 @@
         error = info.errorContent.replace('%id', error.id) + ' ' + info.errorParamsBroken;
         break;
 
+      case 'libraryMissing':
+        error = info.errorLibrary.replace('%lib', error.library);
+        break;
+
       case 'scriptMissing':
         error = info.errorScript.replace('%lib', error.library);
         break;