diff --git a/chrome/content/zotero/preferences/preferences_sync.js b/chrome/content/zotero/preferences/preferences_sync.js
index 7f83bd289..8c6ad507e 100644
--- a/chrome/content/zotero/preferences/preferences_sync.js
+++ b/chrome/content/zotero/preferences/preferences_sync.js
@@ -32,7 +32,7 @@ Zotero_Preferences.Sync = {
 		this.updateStorageSettingsUI();
 
 		var username = Zotero.Users.getCurrentUsername() || Zotero.Prefs.get('sync.server.username') || " ";
-		var apiKey = Zotero.Sync.Data.Local.getAPIKey();
+		var apiKey = yield Zotero.Sync.Data.Local.getAPIKey();
 		this.displayFields(apiKey ? username : "");
 		
 		var pass = Zotero.Sync.Runner.getStorageController('webdav').password;
@@ -286,7 +286,7 @@ Zotero_Preferences.Sync = {
 		var loadingLabel = Zotero.getString("zotero.preferences.sync.librariesToSync.loadingLibraries");
 		addRow(loadingLabel, "loading", false, false);
 
-		var apiKey = Zotero.Sync.Data.Local.getAPIKey();
+		var apiKey = yield Zotero.Sync.Data.Local.getAPIKey();
 		var client = Zotero.Sync.Runner.getAPIClient({apiKey});
 		var groups = [];
 		try {
diff --git a/chrome/content/zotero/xpcom/sync/syncLocal.js b/chrome/content/zotero/xpcom/sync/syncLocal.js
index a684dd14c..e934d23fe 100644
--- a/chrome/content/zotero/xpcom/sync/syncLocal.js
+++ b/chrome/content/zotero/xpcom/sync/syncLocal.js
@@ -42,13 +42,16 @@ Zotero.Sync.Data.Local = {
 	}),
 	
 	
-	getAPIKey: function () {
+	/**
+	 * @return {Promise}
+	 */
+	getAPIKey: Zotero.Promise.method(function () {
 		var login = this._getAPIKeyLoginInfo();
 		return login
 			? login.password
 			// Fallback to old username/password
 			: this._getAPIKeyFromLogin();
-	},
+	}),
 	
 	
 	setAPIKey: function (apiKey) {
diff --git a/chrome/content/zotero/xpcom/sync/syncRunner.js b/chrome/content/zotero/xpcom/sync/syncRunner.js
index f8efc4ef4..44f4c2161 100644
--- a/chrome/content/zotero/xpcom/sync/syncRunner.js
+++ b/chrome/content/zotero/xpcom/sync/syncRunner.js
@@ -33,7 +33,13 @@ if (!Zotero.Sync) {
 Zotero.Sync.Runner_Module = function (options = {}) {
 	const stopOnError = false;
 	
-	Zotero.defineProperty(this, 'enabled', { get: () => _apiKey || Zotero.Sync.Data.Local.getAPIKey() });
+	Zotero.defineProperty(this, 'enabled', {
+		get: () => {
+			if (_apiKey) return true;
+			var username = Zotero.Prefs.get('sync.server.username');
+			return username && Zotero.Sync.Data.Local.getLegacyPassword(username);
+		}
+	});
 	Zotero.defineProperty(this, 'syncInProgress', { get: () => _syncInProgress });
 	Zotero.defineProperty(this, 'lastSyncStatus', { get: () => _lastSyncStatus });
 	
@@ -1267,7 +1273,7 @@ Zotero.Sync.Runner_Module = function (options = {}) {
 
 
 	this.deleteAPIKey = Zotero.Promise.coroutine(function* (){
-		var apiKey = Zotero.Sync.Data.Local.getAPIKey();
+		var apiKey = yield Zotero.Sync.Data.Local.getAPIKey();
 		var client = this.getAPIClient({apiKey});
 		Zotero.Sync.Data.Local.setAPIKey();
 		yield client.deleteAPIKey();
@@ -1313,7 +1319,7 @@ Zotero.Sync.Runner_Module = function (options = {}) {
 	}
 	
 	
-	var _getAPIKey = Zotero.Promise.coroutine(function* () {
+	var _getAPIKey = Zotero.Promise.method(function () {
 		// Set as .apiKey on Runner in tests or set in login manager
 		return _apiKey || Zotero.Sync.Data.Local.getAPIKey()
 	})
diff --git a/test/tests/preferences_syncTest.js b/test/tests/preferences_syncTest.js
index 4d7f987e1..7c8dbe591 100644
--- a/test/tests/preferences_syncTest.js
+++ b/test/tests/preferences_syncTest.js
@@ -69,7 +69,7 @@ describe("Sync Preferences", function () {
 				getAPIKeyFromCredentialsStub.resolves(apiResponse);
 				yield setCredentials("Username", "correctPassword");
 				
-				assert.equal(Zotero.Sync.Data.Local.getAPIKey(), apiKey);
+				yield assert.eventually.equal(Zotero.Sync.Data.Local.getAPIKey(), apiKey);
 				assert.equal(doc.getElementById('sync-unauthorized').getAttribute('hidden'), 'true');
 			});
 
@@ -79,7 +79,7 @@ describe("Sync Preferences", function () {
 				yield setCredentials("Username", "incorrectPassword");
 
 				assert.isTrue(Zotero.alert.called);
-				assert.equal(Zotero.Sync.Data.Local.getAPIKey(), "");
+				yield assert.eventually.equal(Zotero.Sync.Data.Local.getAPIKey(), "");
 				assert.equal(doc.getElementById('sync-authorized').getAttribute('hidden'), 'true');
 			});
 
@@ -87,12 +87,12 @@ describe("Sync Preferences", function () {
 			it("should delete API key and display auth form when 'Unlink Account' clicked", function* () {
 				getAPIKeyFromCredentialsStub.resolves(apiResponse);
 				yield setCredentials("Username", "correctPassword");
-				assert.equal(Zotero.Sync.Data.Local.getAPIKey(), apiKey);
+				yield assert.eventually.equal(Zotero.Sync.Data.Local.getAPIKey(), apiKey);
 
 				yield win.Zotero_Preferences.Sync.unlinkAccount(false);
 
 				assert.isTrue(deleteAPIKey.called);
-				assert.equal(Zotero.Sync.Data.Local.getAPIKey(), "");
+				yield assert.eventually.equal(Zotero.Sync.Data.Local.getAPIKey(), "");
 				assert.equal(doc.getElementById('sync-authorized').getAttribute('hidden'), 'true');
 			});
 			
@@ -103,7 +103,7 @@ describe("Sync Preferences", function () {
 				waitForDialog(null, 'cancel');
 				
 				yield win.Zotero_Preferences.Sync.unlinkAccount();
-				assert.equal(Zotero.Sync.Data.Local.getAPIKey(), apiKey);
+				yield assert.eventually.equal(Zotero.Sync.Data.Local.getAPIKey(), apiKey);
 				assert.equal(doc.getElementById('sync-unauthorized').getAttribute('hidden'), 'true');
 			});
 
diff --git a/test/tests/syncLocalTest.js b/test/tests/syncLocalTest.js
index e3404961e..02202655e 100644
--- a/test/tests/syncLocalTest.js
+++ b/test/tests/syncLocalTest.js
@@ -6,9 +6,9 @@ describe("Zotero.Sync.Data.Local", function() {
 			var apiKey1 = Zotero.Utilities.randomString(24);
 			var apiKey2 = Zotero.Utilities.randomString(24);
 			Zotero.Sync.Data.Local.setAPIKey(apiKey1);
-			assert.equal(Zotero.Sync.Data.Local.getAPIKey(apiKey1), apiKey1);
+			yield assert.eventually.equal(Zotero.Sync.Data.Local.getAPIKey(apiKey1), apiKey1);
 			Zotero.Sync.Data.Local.setAPIKey(apiKey2);
-			assert.equal(Zotero.Sync.Data.Local.getAPIKey(apiKey2), apiKey2);
+			yield assert.eventually.equal(Zotero.Sync.Data.Local.getAPIKey(apiKey2), apiKey2);
 		})
 		
 		
@@ -16,7 +16,7 @@ describe("Zotero.Sync.Data.Local", function() {
 			var apiKey = Zotero.Utilities.randomString(24);
 			Zotero.Sync.Data.Local.setAPIKey(apiKey);
 			Zotero.Sync.Data.Local.setAPIKey("");
-			assert.strictEqual(Zotero.Sync.Data.Local.getAPIKey(apiKey), "");
+			yield assert.eventually.strictEqual(Zotero.Sync.Data.Local.getAPIKey(apiKey), "");
 		})
 	})