I recently purchased a sealed box brand-new Galaxy Tab A9 Plus. After two days of use, I tried adding a new Gmail account. Once I completed the setup and tapped “Done,” the screen went black, the device kept turning on and off, then restarted multiple times automatically before entering "Safe Mode System UI". I took it to the Samsung service center in Lebanon, where they performed a software reset. This only removed it from Safe Mode temporarily, but as soon as I added a new user again, the exact same problem happened: endless restarts and automatic entry into Safe Mode. Once inside, I cannot exit—every attempt triggers the same restart loop, and the device goes back to Safe Mode. Note that I installed nothing from the Play Store so this issue happens while having the build-in Apps only. Despite this, Samsung has not given me any explanation, has not solved the issue, and refuses to replace my tablet.
We’re sorry to hear about the experience with your Galaxy Tab A9+. Since this isn’t expected behavior on a new device, we recommend performing a factory reset and testing the tablet before adding accounts or additional apps.
I just had the exact same thing happen today to a brand new A9+ when I added my daughter as a user. I am awaiting a replacement from my cellular provider, hopefully the new one doesn't do the same thing. I will add that the dealer attempted to do a factory reset and it wouldn't allow him to, hitting the button did nothing.
