diff --git a/app/public/config.js b/app/public/config.js
index 2033b7319..1e8cb6a30 100644
--- a/app/public/config.js
+++ b/app/public/config.js
@@ -117,7 +117,7 @@ export function loadConfigs() {
         count++;
     });
 
-    if (!configs["repository"]) {
+    if (count === 0) {
         configs["repository"] = true;
         firstRun = true;
     }
diff --git a/app/public/electron.js b/app/public/electron.js
index 33135b88d..7a2e1e502 100644
--- a/app/public/electron.js
+++ b/app/public/electron.js
@@ -21,6 +21,9 @@ let tray = null
 let repositoryWindows = {};
 let repoIDForWebContents = {};
 
+if (process.env.KOPIA_CUSTOM_APPDATA) {
+  app.setPath('appData', process.env.KOPIA_CUSTOM_APPDATA);
+}
 
 if (isPortableConfig()) {
   // in portable mode, write cache under 'repositories'
@@ -435,6 +438,7 @@ app.on('ready', () => {
     app.testHooks = {
       tray: tray,
       showRepoWindow: showRepoWindow,
+      allConfigs: allConfigs,
     }
   }
 
@@ -582,6 +586,5 @@ function updateTrayContextMenu() {
     ] },
     { label: 'Quit', role: 'quit' },
   ]);
-
   tray.setContextMenu(Menu.buildFromTemplate(template));
 }
diff --git a/app/tests/main.spec.js b/app/tests/main.spec.js
index 3993416d9..5e464a92c 100644
--- a/app/tests/main.spec.js
+++ b/app/tests/main.spec.js
@@ -1,9 +1,16 @@
 import { test, expect } from '@playwright/test'
 import { _electron as electron } from 'playwright'
 
+import fs from 'fs';
+import os from 'os';
 import path from 'path';
 
+const DEFAULT_REPO_ID = 'repository';
+
 let electronApp
+let mainPath
+let executablePath
+let tmpAppDataDir
 
 function getKopiaUIDir() {
   switch (process.platform + "/" + process.arch) {
@@ -44,22 +51,36 @@ function getExecutablePath(kopiauiDir) {
   }
 }
 
-test.beforeAll(async () => {
-  const kopiauiDir = getKopiaUIDir();
-  expect(kopiauiDir).not.toBeNull();
+/**
+ * Creates a temporary application data directory along with the kopia
+ * directory for testing purposes.
+ *
+ * @returns {string} The path to the created temporary directory.
+ */
+function createTemporaryAppDataDir() {
+  const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'kopia-test-'));
+  fs.mkdirSync(path.join(tmpDir, 'kopia'));
+  return tmpDir;
+}
 
-  const mainPath = getMainPath(kopiauiDir);
-  const executablePath = getExecutablePath(kopiauiDir);
-
-  console.log('main path', mainPath);
-  console.log('executable path', executablePath);
-
-  process.env.CI = 'e2e'
-  process.env.KOPIA_UI_TESTING = '1'
-  electronApp = await electron.launch({
+/**
+ * Launches a new instance of the Electron app with the given app data directory.
+ *
+ * Also captures page errors and console messages and logs them to the console.
+ *
+ * @param {string} appDataDir - the path to the app data directory
+ * @returns {Promise<Electron.App>} - a promise that resolves to the launched app
+ */
+async function launchApp(appDataDir) {
+  const electronApp = await electron.launch({
     args: [mainPath],
     executablePath: executablePath,
+    env: {
+      ...process.env,
+      KOPIA_CUSTOM_APPDATA: appDataDir,
+    }
   })
+
   electronApp.on('window', async (page) => {
     const filename = page.url()?.split('/').pop()
     console.log(`Window opened: ${filename}`)
@@ -73,13 +94,49 @@ test.beforeAll(async () => {
       console.log(msg.text())
     })
   })
+
+  return electronApp;
+}
+
+/**
+ * Waits for Kopia to start up by delaying for a specified duration.
+ *
+ * @returns {Promise<void>} A promise that resolves after the delay.
+ */
+function waitForKopiaToStartup() {
+  return new Promise((resolve) => {
+    setTimeout(() => {
+      resolve();
+    }, 2500);
+  });
+}
+
+test.beforeAll(() => {
+  const kopiauiDir = getKopiaUIDir();
+  expect(kopiauiDir).not.toBeNull();
+
+  mainPath = getMainPath(kopiauiDir);
+  executablePath = getExecutablePath(kopiauiDir);
+
+  console.log('main path', mainPath);
+  console.log('executable path', executablePath);
+
+  process.env.CI = 'e2e';
+  process.env.KOPIA_UI_TESTING = '1';
+})
+
+test.beforeEach(async () => {
+  tmpAppDataDir = createTemporaryAppDataDir();
 })
  
-test.afterAll(async () => {
-  await electronApp.close()
+test.afterEach(async () => {
+  await electronApp.close();
+  fs.rmSync(tmpAppDataDir, { recursive: true, force: true });
 })
  
-test('opens repository window', async () => {
+test('opens repository window on first start', async () => {
+  electronApp = await launchApp(tmpAppDataDir);
+
   await electronApp.evaluate(async ({app}) => {
     app.testHooks.showRepoWindow('repository');
   });
@@ -100,3 +157,51 @@ test('opens repository window', async () => {
     return app.testHooks.tray.closeContextMenu();
   })
 });
+
+test("adds default repository if no repository is configured", async () => {
+  electronApp = await launchApp(tmpAppDataDir);
+
+  await waitForKopiaToStartup();
+
+  const configs = await electronApp.evaluate(async ({app}) => {
+    return app.testHooks.allConfigs();
+  })
+  expect(configs).toStrictEqual([DEFAULT_REPO_ID]);
+});
+
+test("doesn't open repository window if the default repository config exists", async () => {
+  fs.writeFileSync(path.join(tmpAppDataDir, 'kopia', `${DEFAULT_REPO_ID}.config`), '');
+
+  electronApp = await launchApp(tmpAppDataDir);
+
+  await waitForKopiaToStartup();
+  const windows = electronApp.windows();
+  expect(windows).toHaveLength(0);
+});
+
+test.describe("when non-default repository config exists", () => {
+  const NON_DEFAULT_REPO_ID = 'repository-42';
+
+  test.beforeEach(async () => {
+    fs.writeFileSync(path.join(tmpAppDataDir, 'kopia', `${NON_DEFAULT_REPO_ID}.config`), '');
+  })
+
+  test("doesn't open repository window if non-default repository config exists", async () => {
+    electronApp = await launchApp(tmpAppDataDir);
+
+    await waitForKopiaToStartup();
+    const windows = electronApp.windows();
+    expect(windows).toHaveLength(0);
+  });
+
+  test("doesn't add default repository", async () => {
+    electronApp = await launchApp(tmpAppDataDir);
+
+    await waitForKopiaToStartup();
+
+    const configs = await electronApp.evaluate(async ({app}) => {
+      return app.testHooks.allConfigs();
+    })
+    expect(configs).toStrictEqual([NON_DEFAULT_REPO_ID]);
+  });
+})