diff --git a/packages/client-sync/src/local-sync-worker/sync-process-manager.es6 b/packages/client-sync/src/local-sync-worker/sync-process-manager.es6
index ef7edede9..d35448e1a 100644
--- a/packages/client-sync/src/local-sync-worker/sync-process-manager.es6
+++ b/packages/client-sync/src/local-sync-worker/sync-process-manager.es6
@@ -173,7 +173,7 @@ class SyncProcessManager {
   async removeWorkerForAccountId(accountId, {timeout} = {}) {
     if (this._workersByAccountId[accountId]) {
       await this._workersByAccountId[accountId].destroy({timeout})
-      this._workersByAccountId[accountId] = null;
+      delete this._workersByAccountId[accountId];
     }
 
     if (this._localSyncDeltaEmittersByAccountId.has(accountId)) {