diff --git a/packages/backend/migration/1644010796173-convert-hard-mutes.js b/packages/backend/migration/1644010796173-convert-hard-mutes.js
index f06da6567..9f2e9643e 100644
--- a/packages/backend/migration/1644010796173-convert-hard-mutes.js
+++ b/packages/backend/migration/1644010796173-convert-hard-mutes.js
@@ -9,6 +9,7 @@ module.exports = class convertHardMutes1644010796173 {
         for(let i = 0; i < entries.length; i++) {
             let words = entries[i].mutedWords
                 .map(line => {
+										if (typeof line === 'string') return [];
                     const regexp = line.join(" ").match(/^\/(.+)\/(.*)$/);
                     if (regexp) {
                         // convert regexp's