diff --git a/src/config.js b/src/config.js
index 20328e3f60..70152afa60 100644
--- a/src/config.js
+++ b/src/config.js
@@ -423,7 +423,7 @@ export default class Config {
     this.linkFileDependencies = Boolean(this.getOption('yarn-link-file-dependencies'));
     this.packBuiltPackages = Boolean(this.getOption('experimental-pack-script-packages-in-mirror'));
 
-    this.autoAddIntegrity = !boolifyWithDefault(this.getOption('unsafe-disable-integrity-migration'), 'true');
+    this.autoAddIntegrity = !boolifyWithDefault(String(this.getOption('unsafe-disable-integrity-migration')), true);
 
     //init & create cacheFolder, tempFolder
     this.cacheFolder = path.join(this._cacheRootFolder, 'v' + String(constants.CACHE_VERSION));