diff --git a/src/libsync/discoveryphase.cpp b/src/libsync/discoveryphase.cpp
index 02722ceedac9..b6b383e3c9ae 100644
--- a/src/libsync/discoveryphase.cpp
+++ b/src/libsync/discoveryphase.cpp
@@ -697,6 +697,14 @@ void DiscoverySingleDirectoryJob::metadataReceived(const QJsonDocument &json, in
         }
     }
 
+    if (job->signature().isEmpty()) {
+        qCDebug(lcDiscovery) << "Initial signature is empty.";
+        _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
+        emit finished(HttpError{0, tr("Encrypted metadata setup error: initial signature from server is empty.")});
+        deleteLater();
+        return;
+    }
+
     const auto e2EeFolderMetadata = new FolderMetadata(_account,
                                                  _remoteRootFolderPath,
                                                  statusCode == 404 ? QByteArray{} : json.toJson(QJsonDocument::Compact),