diff --git a/chrome/content/zotero/xpcom/storage.js b/chrome/content/zotero/xpcom/storage.js
index 67d3efe5d..03feeb645 100644
--- a/chrome/content/zotero/xpcom/storage.js
+++ b/chrome/content/zotero/xpcom/storage.js
@@ -847,29 +847,29 @@ Zotero.Sync.Storage = new function () {
 	
 	
 	this.purgeDeletedStorageFiles = function (module, callback) {
-		_session = new Zotero.Sync.Storage.Session(module, { onError: _error });
-		if (!_session.initFromPrefs()) {
+		var session = new Zotero.Sync.Storage.Session(module, { onError: _error });
+		if (!session.initFromPrefs()) {
 			return;
 		}
-		_session.purgeDeletedStorageFiles(callback);
+		session.purgeDeletedStorageFiles(callback);
 	}
 	
 	
 	this.purgeOrphanedStorageFiles = function (module, callback) {
-		_session = new Zotero.Sync.Storage.Session(module, { onError: _error });
-		if (!_session.initFromPrefs()) {
+		var session = new Zotero.Sync.Storage.Session(module, { onError: _error });
+		if (!session.initFromPrefs()) {
 			return;
 		}
-		_session.purgeOrphanedStorageFiles(callback);
+		session.purgeOrphanedStorageFiles(callback);
 	}
 	
 	
 	this.isActive = function (module) {
-		_session = new Zotero.Sync.Storage.Session(module, { onError: _error });
-		if (!_session.initFromPrefs()) {
+		var session = new Zotero.Sync.Storage.Session(module, { onError: _error });
+		if (!session.initFromPrefs()) {
 			return;
 		}
-		return _session.active;
+		return session.active;
 	}