diff --git a/src/crypto/algorithms/megolm.js b/src/crypto/algorithms/megolm.js
index 115a8ee9b..94b991437 100644
--- a/src/crypto/algorithms/megolm.js
+++ b/src/crypto/algorithms/megolm.js
@@ -758,7 +758,7 @@ MegolmDecryption.prototype.decryptEvent = async function(event) {
     } catch (e) {
         let errorCode = "OLM_DECRYPT_GROUP_MESSAGE_ERROR";
 
-        if (e && e.message && e.message === 'OLM.UNKNOWN_MESSAGE_INDEX') {
+        if (e && e.message === 'OLM.UNKNOWN_MESSAGE_INDEX') {
             this._requestKeysForEvent(event);
 
             errorCode = 'OLM_UNKNOWN_MESSAGE_INDEX';