My laptop does not have a led or anything to show whether the caps lock is on or not, and while Kubuntu warns you on the lockscreen about whether your caps lock is on or not, Ubuntu seems to lack it. If you try to put in a password somewhere inside the settings or anything, then you get a little warning triangle right in the box, but there is nothing like that on the lockscreen, when trying to type the user password.
This makes the entire process a bit more difficult - if you are using a password with both uppercase and lowercase letters. Especially since you can accidentally and very easily make mistakes.
Is there a way to add such an indicator to the lockscreen? I've looked online, and I've seem some people recommending the installation of an app, but I don't think that it would work on the lockscreen.
Update: It doesn't show the caps lock warning if the system was recently rebooted. If the system is shut down and I start it, it won't show the warning if I'm typing the password for the first time.
If I however just lock the screen and then try to type the password, it shows it:
I haven't made any sort of changes, it happens both on fresh installs of Ubuntu 18.04 and 18.10.
I too am having this problem. It seems the Caps Lock button doesn't work on the lock screen if you are entering a password. This results in much frustration and often I had to restart my computer to log back in. However I found a workaround that might help:
Not the best solution but I couldn't get anything else to work.