If your Samsung Galaxy Tab S9 is completely black and won't respond, the first thing to try is a force restart. Press and hold the Volume Down button and the Side button (power button) together for about 10 seconds. Keep holding them until you see the Samsung logo appear on the screen, then release. This is the equivalent of pulling the battery and often clears up temporary software glitches that cause an unresponsive screen.
Check Your Charger and Cable
This is a surprisingly common fix for the Tab S9. The tablet supports 45W Super Fast Charging, but it won't charge quickly, or sometimes at all, with a weaker phone charger. If you're using a standard 15W or 20W phone charger, the tablet might be draining its battery faster than the charger can replenish it, especially if the screen is on.
For the best results, use the official Samsung 45W charger that came with your tablet. If you don't have it, try any high-wattage USB-C PD (Power Delivery) charger you have. Plug it into a wall outlet, not a computer or car port, and let it charge undisturbed for at least an hour with the screen off.
Also, inspect the USB-C port on the bottom of your tablet. Lint and pocket debris can get packed in there, preventing the cable from making a solid connection. Use a wooden toothpick or a can of compressed air to gently clear it out.
Boot Into Safe Mode
If the tablet turns on but gets stuck on the Samsung logo or freezes during startup, a recently installed app could be the culprit. Booting into Safe Mode temporarily disables all third-party apps.
First, force restart the tablet as described above. The moment you see the Samsung logo appear, release the Side button but keep holding the Volume Down button. Continue holding it until you see "Safe Mode" in the bottom-left corner of the screen. If the tablet boots successfully this way, you'll know a downloaded app is causing the problem.
From here, you can go to Settings > Apps, sort by "Last installed," and start uninstalling recent apps one by one until the normal boot works again.
Clear the System Cache
Corrupted data in the system cache can prevent a clean startup. Clearing it doesn't delete any personal files like photos or messages, so it's a safe next step. You'll need to boot into the Android Recovery Menu.
Make sure the tablet is powered off. Connect it to the charger, then press and hold the Volume Up button and the Side button simultaneously. When the Samsung logo appears, release only the Side button but keep holding Volume Up until the blue "Android Recovery" menu loads.
Use the Volume Down button to scroll to "Wipe cache partition" and press the Side button to select it. Confirm the action, then select "Reboot system now" when it's done. This process can fix boot loops and update-related glitches.
Consider Your Usage Mode
The Galaxy Tab S9 has a powerful feature called Samsung DeX that turns your interface into a desktop-like experience. I've seen this be a factor because DeX mode increases power consumption significantly. If you were using DeX with a low-wattage charger plugged in, the tablet might have been slowly discharging the entire time, leading to a sudden shutdown.
Similarly, charging with the screen on is much slower. For the fastest charge, always let the tablet charge with the screen off. If you need to use it while plugged in, make absolutely sure you're using a 45W charger to keep up with the power demand.
Perform a Factory Reset
If all else fails, a factory reset is the final software step. This will erase everything on your tablet, apps, accounts, photos, and settings, returning it to its original out-of-the-box state. You should only do this if your data is backed up to Samsung Cloud or Google Drive.
To start, power the tablet off. Enter the Recovery Menu again by holding Volume Up and the Side button. In the menu, use the volume keys to navigate to "Factory data reset" or "Wipe data/factory reset" and select it with the Side button. You'll need to confirm your choice and then wait for the process to complete before selecting "Reboot system now."
