4 Common Mistakes That Can Invalidate Your Duolingo English Test 2026
An invalidated Duolingo English Test (DET) can mean that you lose the test fee and have to retake the test. Most invalidations come from honest mistakes, not cheating. Four rules cause most of these invalidations. This article explains what each one is, and exactly how to avoid it.
Table of Contents
- Don't Run Other Apps During the Test
- Don't Look Away from Your Screen
- Don't Use Predictive Text or Writing Assistants
- Don't Let Your Phone Camera Move
- What to Do If Your Test Was Not Certified
Don't Run Other Apps During the Test
This is the most commonly broken rule. When you take the DET, the desktop app should be the only program running on your computer.
Before you start the test, close every other app. This includes:
- Web browsers like Chrome, Safari, and Firefox
- Messaging apps like WhatsApp and Slack
- Video call and chat apps like Skype, Discord, and Zoom
- Streaming apps like Twitch and Spotify
- Remote desktop apps like TeamViewer and AnyDesk
A safer step is to uninstall any app that can make video calls, share your screen, check your spelling, or use your webcam. You can install them again after the test.
Also close any program running in the background. On Windows, check the system tray and Task Manager. On Mac, right-click each app icon in the dock and choose Quit. Never take the test on a virtual machine.
Does It Matter If My Browser Is Open in the Background?
Yes. Even if you are not using your browser, it counts as another program running on your computer. Close it before you start the test.
What About System Processes Running in the Background?
Background programs can also cause an invalidation. On Windows, open Task Manager and the system tray to see what is running. On Mac, right-click each icon in the dock and choose Quit. Close everything that is not the DET app.
Can I Take the DET on a Virtual Machine?
No. Virtual machines are not allowed. You must take the test on a real computer with the DET desktop app installed directly on it.
Don't Look Away from Your Screen
The second most common mistake is looking away from the screen during the test. Many students worry about this, so it helps to know exactly what is allowed.
Looking down at your keyboard to type is fine. That will not affect your certification. The problem is looking away during speaking sections, or looking away for a long time when you are not typing.
During speaking tasks, keep your eyes on the screen. If you need a moment to think before you answer, that is fine. Just keep your eyes forward.
Is It Okay to Look Down When I Type?
Yes. Glancing down at your keyboard while you are typing is fine. It is a normal part of writing on a computer and does not affect your certification.
What Counts as "Looking Away" During a Speaking Section?
During a speaking task, your eyes should stay on the screen. Looking up, looking to the side, or looking down at your keyboard for a long time can all count as looking away. If you need to think before you speak, look forward at the screen while you think.
Can I Look Away at All?
You can briefly glance down to type during writing tasks. That is the only safe time to look away. During speaking tasks and long pauses, keep your eyes on the screen.
Don't Use Predictive Text or Writing Assistants
The third rule is about tools that help you write. Many students do not expect this rule, so it is important to check your computer before the test.
Predictive text is when your keyboard suggests full words after you type the first few letters. Writing assistants are tools like Grammarly that correct or improve your writing as you type. Neither is allowed on the DET.
Before your test, do these steps:
- Turn off any non-Latin keyboard input method, like pinyin, in your computer's keyboard settings.
- Close or uninstall Grammarly, ProWritingAid, or any similar writing tool.
- On Mac, right-click each app icon in the dock and choose Quit.
- On Windows, clear the system tray to make sure no writing tool is running in the background.
This takes only a few minutes and can save you problems later.
Is Grammarly Allowed During the DET?
No. Grammarly is a writing assistant, and writing assistants are not allowed on the DET. Close or uninstall it before you start the test.
What Counts as a Writing Assistant?
A writing assistant is any tool that suggests, corrects, or improves what you type. Grammarly, ProWritingAid, and Microsoft Editor are all writing assistants. Built-in autocorrect or spellcheck in your operating system also counts. Turn all of these off before the test.
What If I Have More Than One Input (Like Pinyin)?
Turn off any non-Latin input method before the test. Many non-Latin inputs, like pinyin, work like predictive text and are not allowed. Only use a standard Latin keyboard layout during the DET.
Don't Let Your Phone Camera Move
The fourth rule is about your phone, which records you during the test. Your phone camera must show your full computer screen and your keyboard for the whole test. If the camera moves and the full view is lost, your test will be invalidated.
Before you start, check your computer screen to make sure your keyboard and full screen are visible in the camera frame. To keep the phone stable:
- Lean it against something heavy that will not move
- Place it horizontally rather than vertically
- Put it on a flat, solid surface
Turn on Do Not Disturb on your phone, and check that no contacts are set to bypass it. An unexpected call or notification could disrupt the test.
Once the test begins, do not touch your phone. If it falls or shifts during the test, reposition it and continue.
Where Should I Position My Phone for the DET?
Place your phone so the camera can see both your full computer screen and your keyboard. Horizontal orientation is the most stable. Lean the phone against something heavy and place it on a flat surface so it does not move during the test.
What Happens If My Phone Moves During the Test?
If your phone moves and the camera can no longer see your full screen and keyboard, your test will be invalidated. If it falls or shifts during the test, reposition it right away and continue. Do not stop the test.
Should My Phone Be on Do Not Disturb?
Yes. Turn on Do Not Disturb before the test starts. Also check that no contacts are set to bypass it, because a call or notification could interrupt your test.
What to Do If Your Test Was Not Certified
These four rules cover most invalidations on the DET. If you follow them, your test should be certified. If your test was not certified, you still have options. See our guide on what to do if your Duolingo English Test was not certified for the next steps.