Aspire ES1-531 Win 10 Home 1809 (clean install). From boot, the login screen displays as "password incorrect please try again". If I hit Enter enough times, it eventually allows me to enter the password and things proceed as normal. It is a local account and there is only the one on the PC.
Mouse/touchpad and keypad drivers are the latest versions, as is the BIOS. I've tried disabling and then re-enabling the password required option using netplwiz and I've tried changing the password. Also tried disabling the auto login default after Windows update.
If there's a character is typed before you can get to do it yourself, I would suggest turning the keyboard upside over your shoulder as if you were burping your baby, and pat its back until all the toast crumbs fall out.
Yeah, I was thinking a hardware issue but if it was a stuck key or something weird going on with the touchpad button then I would expect peculiar behaviour after logging in also, eg: random clicks or keypresses in a blank Notepad document. They don't happen.
I wonder if it would throw an error if I stripped it down and disconnected the keyboard and touchpad cables, then attached the external kb and tp via usb sockets before booting. I've stripped plenty of laptops in the past, replaced kbs and screens etc but never needed to do this.
Unless the keyboard isn't turning off when you connect the external one, which it should, the keyboard itself may well not be the issue. Can't hurt to try, however, if it is say a motherboard issue, that won't resolve it.
Yes, the onscreen keyboard works but it is quicker just to hit the Enter key three or four times until the "ok" button is gone and the password box appears. Once that box is on the screen, I can enter the password just fine.
Unplugging the internal human interface cables and relying solely on the external usb keyboard and mouse did not make any difference. Since this is a clean install of Windows 10 Home v 1809, there won't be anything among the startup entries that doesn't exist in other new installations. I did the clean installation because everything else I had tried had failed.
It does look like some weird event triggering on the mobo and since it is more of an annoyance than a critical situation (yet!), I'm giving up looking for it. Thanks to both of you for your suggestions, which were much appreciated. I've never recommended anyone buy an Acer and tend to see more of them in for repair than any other manufacturer - although that may be because more of them are sold in the first place, I remain fairly convinced that they're a false economy compared to equivalent Dell models etc.