Unlock screen requires several tries to open phone.

[lolee2771]

I press me home button and it pulls up my lock screen, I then swipe the lock screen to the right to reveal my passcode screen but when I enter my pin the screen makes a clicking sound and either immediately goes back to a black screen off or shows my home screen for a split second then goes back to the black screen off position. I have to repeat these steps anywhere from 3 to 15 times before my phone will stay unlocked and I'm able to use my phone. I've tried deleting some of my recently installed and unnecessary apps and I have moved any that can be moved over to my SD card and this has provided minimal improvement. I turned my Wi-Fi off and airplane mode on last night while I slept and my phone opened prefect this morning but as soon as I turned the Wi-Fi back on and the airplane mode off my phone went to the black screen off mode again and I had to go through the above process off swiping and entering my pin over and over to get it to open back up again. Does anyone have any idea why this is happening or what I can do to fix this issue? Any help is greatly appreciated bc I'm so close to throwing it up against the wall.

 

[B. Diddy]

Welcome to Android Central! Does this also happen in Safe Mode? https://support.t-mobile.com/docs/DOC-28008

 

[lolee2771]

Welcome to Android Central! Does this also happen in Safe Mode? https://support.t-mobile.com/docs/DOC-28008

No, I haven't. I didn't even know how to start safe mode until I read the instructions attached to the link you sent. How do I know which app is causing the problem or which one I need to delete? Thank you for your help. It is appreciated more than you will ever know.
I am sorry if you received this reply twice but I don't know if I hit the right option the first time I sent it bc I don't see it in the feed.

 

[Javier P]

Welcome to the forums. It's difficult to know for sure which app is causing that issue. Free games, flashlights, cleaner apps, memory boosters, photo editors ...

See if there's any unusual app checked as device administrator in the security settings.

 

[B. Diddy]

No, I haven't. I didn't even know how to start safe mode until I read the instructions attached to the link you sent. How do I know which app is causing the problem or which one I need to delete? Thank you for your help. It is appreciated more than you will ever know.
I am sorry if you received this reply twice but I don't know if I hit the right option the first time I sent it bc I don't see it in the feed.

Unfortunately, there's no easy way to pinpoint the culprit app. Safe Mode can at least narrow the problem down to some app you installed vs a preinstalled app, but if it's the former, you may just have to uninstall apps one by one until the problem goes away.

 

[lolee2771]

Unfortunately, there's no easy way to pinpoint the culprit app. Safe Mode can at least narrow the problem down to some app you installed vs a preinstalled app, but if it's the former, you may just have to uninstall apps one by one until the problem goes away.

Thank you so much for your help. I'll let you know when I get my phone working right and I'll tell you what finally worked. Have a great day.

 

[B. Diddy]

I'm copying here what you sent me as a PM, just so we can continue the discussion on the forums:

"I started my phone on safe mode and deleted every app that I have downloaded recently and all apps that I have not used recently but my phone still locks on it's own and then takes me what seems like forever to finally get it to unlock so I can get back in. I pressed my power, volume ^ and home key at the same time to bring up the boot screen so I could clean the chach partition but when the little blue words came up in the left top corner of gave screen it immediately showed the little Android with the little working ball in his stomach and said " installing system update" but after about 45 sec the android fell over on his side and had a yellow triangle with a exclamation point inside the triangle above him and said "NO COMMAND". Is that bad and do I need to do a factory reset?"

This makes me wonder if there's a problem with your Power button -- it might be intermittently getting stuck in a pressed state. This might be why the screen keeps going to sleep against your wishes, and could also explain why you're unable to select Wipe Cache Partition in the Recovery Menu. It's possible that while you're scrolling down to the Wipe Cache option, the Power button inappropriate activates, maybe when the cursor is at the "Apply from SD card" option, which I think would give you that "Installing System Update" screen. If the Power button is faulty, you'd have to bring the phone to a repair shop (or, if it's still under warranty, contact Samsung).