Windows 10 Logon screen flashing/busy.

Error Message read:

LogonUI.exe - Application Error

The instruction at 0x00007ffa704e5b90 referenced memory at 0x0000000000000008. The memory could not be read.

Click on OK to terminate the program.

Tinkerer said:

Hello, I'm new to the forum here.

I'd like to ask if anyone has had a problem with the logon screen with windows 10.
I upgraded on the morning of Saturday 8th August, without any serious problems. However, later on in the afternoon, I had to do a restart, after a virus/malware scan and removal of infections. The OS was updated at this point, after which a serious problem occurred. Once the OS reached the logon screen, it started flashing on and off between Logon screen and time/date start up picture, with the cursor showing busy. It also reported an error message to do with LogonUI .
I had no way to Logon, or to open task manager, so i had to boot into safe mode, and attempt various problem solving solutions read elsewhere for this issue on the net. None of these worked, so i had to roll back to Windows 7 for the time being. Should i upgrade again, this issue will have to be resolved.
Finally, though, i'm led to believe that LogonUI is malware, and not an important system file, but should it be removed, would this be the cause of the issue?

Any help on this subject be greatly appreciated.

I experienced something similar to this. After my first reboot post Windows 10 install, the login screen just flashed, as if there was a loose connection in my VGA cable, or TV interference. The effect being I couldn't login or use my machine.

After much research trawling the 'net, it seems that 'FastAccess', a product from Sensible Vision, that came with my 3 month old Dell laptop, isn't compatible with Windows 10. Or at least the version I had isn't compatible. Sorry, I don't know which version it was.

To disable it, I had a bit of a nightmare getting into Safe Mode and could only get to a command prompt. As I wasn't able to uninstall it from the command prompt, to prevent it starting at boot I renamed the FastAccess folder within c:\Program Files (x86), giving it the extension '.old'. Actually, I can't remember if that was in a 'SensibleVision' folder. Either way, renaming either of these will have the same effect.

I rebooted and voila!, a normal login screen. As I wasn't using FastAccess and didn't want it, I uninstalled it (after removing the '.old' from the folder to allow the uninstaller to do a clean job). All now seems to work fine (I only did this a couple of days ago).

Hope this helps.

Thanks for the reply! As far as I'm aware, I don't have FastAccess installed on my PC. However, something on Windows is the cause, either a process, driver, or program. Finding out which one though, is the hard part...

Looking around for information on the net again. The issues connected to LogonUI that I'm having, have also been reported in Windows 7.

Gerrard said:

I experienced something similar to this. After my first reboot post Windows 10 install, the login screen just flashed, as if there was a loose connection in my VGA cable, or TV interference. The effect being I couldn't login or use my machine.

After much research trawling the 'net, it seems that 'FastAccess', a product from Sensible Vision, that came with my 3 month old Dell laptop, isn't compatible with Windows 10. Or at least the version I had isn't compatible. Sorry, I don't know which version it was.

To disable it, I had a bit of a nightmare getting into Safe Mode and could only get to a command prompt. As I wasn't able to uninstall it from the command prompt, to prevent it starting at boot I renamed the FastAccess folder within c:\Program Files (x86), giving it the extension '.old'. Actually, I can't remember if that was in a 'SensibleVision' folder. Either way, renaming either of these will have the same effect.

I rebooted and voila!, a normal login screen. As I wasn't using FastAccess and didn't want it, I uninstalled it (after removing the '.old' from the folder to allow the uninstaller to do a clean job). All now seems to work fine (I only did this a couple of days ago).

Hope this helps.

Man, this helps a lot. I have the same problem with my Dell. One question: how did you get to a command prompt from the login screen?

RegNatarajan said:

Man, this helps a lot. I have the same problem with my Dell. One question: how did you get to a command prompt from the login screen?

Shut the PC off, then reboot while pressing F8. You should then enter the safe mode menu. Choose "Safe Mode with networking" recommended. This will allow you to surf the net for more info if you need it, and allow you to use command prompt.

Tinkerer said:

Looking around for information on the net again. The issues connected to LogonUI that I'm having, have also been reported in Windows 7.

Also, BitDefender antivirus seems to be a possible cause of the flashing Logon in Windows 7. I don't have BitDefender installed, but I had something called bit BitRaider installed, which I've just removed. However, how this effects Windows 10 in the same fashion, I'm yet to ascertain.

RegNatarajan said:

Man, this helps a lot. I have the same problem with my Dell. One question: how did you get to a command prompt from the login screen?

I appreciate the input but I've tried that a bunch of times with no success. It boots so fast that I can't get it to take. I've even tried holding down F8 (and shift-F8) from before touching the power button all the way through to full boot. If I can get to a command prompt, I'll be fine -- I can just do what the guy above said and cripple the Dell bloatware that's causing this.

Just answering my own question here. I downloaded the Windows 10 media creation tool and made a bootable USB key with it. That got me into a command prompt but I found I didn't even need it as just booting to it and letting it update fixed my problems. Here's the tool that lets you make a bootable Windows 10 key.

Windows 10