Galaxy S26 and S26+ Problems: Exynos Heat, One UI 9 Bugs, Fixes

The update finishes, the phone restarts, and instead of your home screen you get a setup page with a block of XML and the words “Access Denied”. That One UI 9 bug is the newest of the Galaxy S26 problems owners are posting about. The older one is heat: the Exynos 2600 version of the S26 and S26+ runs warm in games and slows down to cope.

Both have fixes you can try at home, and neither needs a factory reset to start with.

Stuck on “Access Denied” after One UI 9

After installing One UI 9 (Android 17) and rebooting, the phone stops on a setup screen showing the XML “Access Denied” error and never reaches the home screen.

According to Sammy Fans (12 October 2026), owners of the Galaxy S26, S25 and S24 series and some foldables have run into it. Samsung hasn’t confirmed a cause, and one tipster suspects a server-side change. In a separate case, Cybernews reports that Samsung acknowledged a setup lockout on some S26 Ultra units, which it said happens when an unstable Android System WebView is used on certain networks.

Try these in order. None of them deletes your data.

1. Cut the phone off from the internet. Switch off the Wi-Fi router or pull the SIM for now, then restart.
2. Force restart by holding Side button + Volume down for about 10 seconds.
3. Boot into Safe Mode. Hold the side key (or Side + Volume down) to get the power menu, long-press Power off and tap Safe mode. Once there, turn off Wi-Fi and mobile data and restart normally.
4. When you reach the home screen, update Android System WebView from the Play Store, sign in to your Samsung account and reconnect.
5. Some owners found that simply trying again later worked, which fits the server-side theory.

Which models have the update, and which builds fix what, is in our One UI 9 rollout tracker.

Which chip is in your S26?

The heat complaints depend almost entirely on the processor. The S26 and S26+ use Qualcomm’s Snapdragon in the US and Samsung’s own 2nm Exynos 2600 in most other regions. The S26 Ultra uses Snapdragon everywhere. Our S26 series chip and Knox explainer has the full split.

Open Settings › About phone and look at the model number. US models usually end in U or U1; international ones end in B or another letter. Every suffix is decoded in our page on the Samsung model number and CSC, and a Samsung Info report confirms model, region and warranty from the IMEI.

Exynos 2600 heat and throttling in games

You’ll notice it as warmth even in menus, real heat during long gaming sessions, and frame rates that sag after several minutes.

Android Authority put an Exynos 2600 Galaxy S26+ up against phones running the Snapdragon 8 Elite Gen 5:

So the Exynos model isn’t broken. It runs hotter and throttles sooner, and Samsung won’t treat that as a fault.

What you can change:

1. Switch to the Light performance profile. Depending on the build it sits under Settings › Device care or Settings › Battery. You give up a little speed and it runs cooler.
2. In a game, swipe up for the Game Booster panel and pick a lower-power or battery-saving setting. Turn off any “maximum” performance mode.
3. Cap the frame rate and graphics inside the game. 60 fps draws far less power than 120.
4. Don’t play on the charger, and take a thick case off for long sessions.
5. Close background apps and check Settings › Battery for anything using power while you aren’t.

Heat with the screen off, overheating warnings during light use, or a shutdown from heat is a different matter. That isn’t normal on either chip, so back up and book a Samsung service check.

Battery drain since One UI 9

Idle drain goes up, or screen-on time shrinks, after the update. Cybernews notes the same complaints from S24 and S25 owners.

After a big update Android re-optimises apps and rebuilds caches, and apps not yet updated for Android 17 can misbehave. Sammy Fans suggests the optimisation can take up to about two weeks. Samsung has told users whose drain doesn’t settle to book a service appointment.

1. Update every app in the Play Store and the Galaxy Store.
2. Check Settings › Battery (usage since last charge) for an app with heavy background use, and restrict or reinstall it.
3. Put rarely used apps into Sleeping or Deep sleeping under background usage limits.
4. Turn on Adaptive battery, plus Battery protection if the phone lives on a charger.
5. Restart once a day for a few days. If drain stays high, wipe the cache partition (below).
6. Still draining after two weeks? Back up and contact Samsung.

Wiping the cache partition

This clears temporary system files left over from the previous version. Photos, apps and accounts stay put.

1. Turn the phone fully off.
2. Connect a USB-C cable to a computer or charger. Recent Galaxy phones need a cable attached to enter recovery.
3. Hold Volume up + Side button until the Samsung logo shows, then let go.
4. Use the volume keys to reach Wipe cache partition, press Side to select it, and confirm.
5. Pick Reboot system now. The first boot can take a little longer.

Wipe data/factory reset sits on the same menu. Leave it alone unless you have a full backup, because it erases the phone.

Apps crash or stutter after the update

Boot into Safe Mode as described above. If the crashes or lag stop, a third-party app is to blame, so uninstall recent apps one at a time. If it carries on in Safe Mode, clear the app’s cache in Settings › Apps › [app] › Storage › Clear cache, update Android System WebView and Google Play services, and look in Settings › Software update for a newer build.

Checking a used S26 before you hand over money

The S26 is all over resale sites now, often imported. Before you pay:

• Read the model number so you know whether it’s Exynos or Snapdragon. If you game a lot, it matters.
• Make sure the seller has signed out of both the Samsung account and the Google account, and run a carrier and SIM-lock check.
• Confirm the IMEI is clean with a Verificação de blacklist GSMA.
• Play a game for 10 minutes. An Exynos unit will get warm, but it shouldn’t shut down.