If your OnePlus 13 screen is stuck in one orientation and won't flip when you turn the phone, you're dealing with a classic auto-rotate glitch. It's a common hiccup that can usually be sorted out in a minute or two. Let's get your screen rotating again.
The quickest thing to try is pulling down the notification shade from the top of your screen. Look for the auto-rotate icon, which looks like a phone with two curved arrows around it. Tap it once to toggle it on if it's grayed out. You should see it light up, usually turning blue or green.
Check the Quick Settings Panel
Sometimes the toggle in the notification shade is just a shortcut. For the full settings, pull down the notification shade twice to expand the Quick Settings panel. Long-press on the auto-rotate icon there. This should open a more detailed menu where you can ensure the main "Auto-rotate" switch is enabled.
In OxygenOS 15, you might also see an option here for "Portrait lock" or something similar. Make sure that's turned off. I've seen this setting get enabled accidentally when the phone is in a certain orientation, locking it in place.
Restart Your OnePlus 13
A simple restart clears out temporary software bugs that can confuse the accelerometer. Just hold the power button until the power menu appears, then tap "Restart." Wait for the phone to fully boot back up and test the rotation again in an app like YouTube or your photo gallery.
If a standard restart doesn't do the trick, try a force restart. This is a bit more thorough. Press and hold the Volume Down button and the Power button together for about 10 seconds. You'll feel the device vibrate and then restart. This doesn't delete any data, it just gives the system a harder reset.
Update OxygenOS
Early software builds can have little bugs, and rotation sensor issues are a classic example. OnePlus is usually pretty quick to patch these things. Head to Settings > About device > OxygenOS version and tap "Check for update."
If an update is available, install it. It's a good habit to keep your OnePlus 13 updated anyway, as it helps with battery life and overall stability. Make sure your phone is connected to Wi-Fi and has a decent charge, preferably over 50%, before starting the update.
Test the Sensors in Diagnostic Mode
Your OnePlus 13 has a built-in diagnostic tool to check if the hardware sensors are working. Open your Phone app and dial *#808#. This will launch the engineering mode test menu.
Look for an option labeled "Sensor" or "Accelerometer test." Tap it, and you'll see a screen with data from the sensors. Tilt and rotate your phone. You should see the X, Y, and Z axis values change in real-time. If they don't budge at all, it could point to a deeper hardware issue.
Check for Problematic Apps
Does the rotation fail only in one specific app, like your web browser or a game? Some apps are programmed to work in only one orientation. Test it in a few different apps to see if the problem is universal or isolated.
If it started after installing a new app, that app might be causing a conflict. Try booting into Safe Mode. Hold the power button, then long-press the "Power off" option on your screen until you see a prompt to reboot to Safe Mode. In this mode, all third-party apps are disabled. If auto-rotate works here, a recently installed app is likely the culprit.
Clear Cache for the Android System
Corrupted system cache can cause all sorts of odd behavior. Clearing it is safe and won't touch your personal data. Turn off your OnePlus 13 completely. Then, press and hold the Volume Down and Power buttons together until the OnePlus logo appears, then release.
You'll enter recovery mode. Use the volume buttons to navigate to "Wipe data and cache" and press the power button to select. Then choose "Wipe cache" and confirm. Once it's done, select "Reboot" to start your phone normally.
Consider a Factory Reset
This is your last resort software fix. Before you do this, make absolutely sure you have a complete backup of your photos, messages, and app data. A factory reset will erase everything and return the phone to its out-of-the-box state.
You can initiate it from Settings > Additional settings > Back up and reset > Erase all data (factory reset). If the rotation issue is caused by deep-seated software corruption, this will wipe it clean. After the reset, test the rotation before you start restoring your apps, just to be sure.
If you've tried every software fix here, including a factory reset, and the diagnostic test showed no sensor movement, the issue is likely physical. The accelerometer could be damaged from a drop, or there might be a loose connection inside. At that point, contacting OnePlus support for a repair assessment would be the next step.