diff --git a/src/matrix/e2ee/megolm/keybackup/KeyBackup.ts b/src/matrix/e2ee/megolm/keybackup/KeyBackup.ts
index 998fb67f..e97eb0cf 100644
--- a/src/matrix/e2ee/megolm/keybackup/KeyBackup.ts
+++ b/src/matrix/e2ee/megolm/keybackup/KeyBackup.ts
@@ -93,7 +93,7 @@ export class KeyBackup {
                     this._hasBackedUpAllKeys = true;
                 } catch (err) {
                     this._stopped = true;
-                    if (err.name === "HomeServerError" && err.errcode === "M_WRONG_ROOM_KEYS_VERSION") {
+                    if (err.name === "HomeServerError" && (err.errcode === "M_WRONG_ROOM_KEYS_VERSION" || err.errcode === "M_NOT_FOUND")) {
                         log.set("wrong_version", true);
                         this._needsNewKey = true;
                     } else {