I started up my ubuntu and it lead to a login prompt. I input the correct password for the account. It went to a black screen for a flash, but it made the default "bongo" error sound and aborted back to the same prompt. No error was displayed.  I know this is the right password, because inputting any other password will make the prompt say "Invalid Login". Only the correct password causes the error.  Also, on that note, my account is set to automatic login.  What can be done to fix this?
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My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back.   I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M
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I used to have a password prompt but then I, from somewhere in User Accounts, unchecked "Require a password for login." Now, I want Ubuntu to prompt for a password again at login screen, mainly because I have to manually unlock the login keyring whenever I access Dash or other services, which is a pain at best.  I also searched another question, namely . It was of no help because the OP's question is "I have a password but Ubuntu doesn't ask for it."  Also, the two answers provided there don't solve my problem at all. They discuss completely other things.  Is there no simple mechanism? Because intuitively, if there's a checkbox option to bypass password requirement, there should be an equally hassle-free facility to again require the password.
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After I read  I noticed that there is a user account named 'nobody' in my Ubuntu system.   Also I noticed that I can login in this account from terminal using the following command and my password:  sudo su nobody     It doesn't mind me at all, but I want to know what is the purpose of this user? Is it created by default on a fresh install of Ubuntu or is created by installing a particular package?
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I have frequently bumped into this issue: sites ask for my password (e.g. Stack Exchange itself) when I want to do something like updating my profile. This is per se a low priority site for me so I use my weakest password in mind that fits the minimum requirements. The event (profile update) is also rare so I forget my password completely. I then face the issue of not being able to login then go to the password reset screen where the criteria are written black and white. After that I return to the login screen and enter the correct password.    The question is not whether or not I am a moron but why the criteria are not shown when I mess up my password for the first time.  An example to weakest password:   Anything is permitted: dodge  Uppercase and lowercase needed: Dodge At least 8 characters and uppercase: Dodgerman At least 8 + uppercase &amp; number needed: Dodge1014
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My Ubuntu 14.04 is stuck when trying to login my desktop. The screen goes black and soon after that the login screen comes back.   I followed all steps in  but the issue was not solved.
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When I boot Ubuntu 10.04.3 from a live CD, it asks me to enter a username and password. I have not booted before, and I haven't created an account.
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The problem can be reproduced as follows:   When I remove the password of an administrator account, "Log In without Password", I cannot use that account to authenticate. When I do something that requires authentication, I cannot use an admin without a password to authenticate. If I leave the password box blank without a password while choosing a non-password admin, authentication fails (in terminal or in GUI).   How to fix this problem?
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Possible Duplicate:          I've just had someone install Ubuntu 12.04. I am not a techie - just a user. I am now asked for a password which I do not have and has never been set. Is there a default one? Otherwise I have to work as a guest all the time... Not so great. I appreciate any help.
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I installed Ubuntu 12.10 and entered a password in SeaHorse. I would like to remove the password of "Default" but I get this error :  GDBus.Error:org.freedesktop.Secret.Error.NoSuchObject: The collection does not exist   Is there a fix or a way to bypass modify the password ?
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Say you type in passwd and you enter in the wrong password. There's a noticeable delay between when it tells you that the password was bad and when you enter it. Any ideas as to why? Seems kinda strange...  Here's the message I'm getting when I enter in a bad password is as follows:  passwd: Authentication token manipulation error passwd: password unchanged   Maybe it's attempting to protect against brute force attempts by reducing the speed with which new passwords can be tried?  Either way is there some discussion of this behavior somewhere? I don't see any note of it in the man page..
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After running a VM and logging out, I got a black screen. I powered off and re-started but got the same after the bios option in start up passed. Several attempts went bye with the same result. So I fiddled with bios boot options a bit and was able to get to a different looking Ubuntu start up screen which, after entering pass key would run a series of commands that were too numerous and frantic to make out. They appeared to be overlapped/layered (the text that is) and seemingly repeating endlessly. I had to power down to get it to stop and re-booting just had the same effect. Finally, I hit the down arrow key when prompted for "disk sda5_crypt" at the pseudo Ubuntu log-in screen I mentioned before. This brought me to an all black screen which read something like:  lvmetad not active cannot process volume group "umbuntu-vg" unlock disk sda5_crypt**   From here I entered a password and Ubuntu start up ran.  That was an unsettling hour or so and I'd like to avoid that in the future. Any ideas what caused it and how to avoid it going forward?  Should have said this before but Ubuntu is the only OS on my machine and my optical drive cannot be opened manually.
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I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:
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I can boot into Ubuntu just fine as a guest but it refuses to accept my login name and password that were set during the Wubi install. I reinstalled it again with basic login and password just to make sure and it still won't let me in.
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I upgraded from 16.04 to 18.04. When I press Ctrl+Alt+F3 I get the terminal which prompts for the username. When I type my username and press Enter, it doesn't wait for my password (its as if I pressed Enter without entering anything). Even if I enter something, the text shown in plaintext and then it keeps on saying my password is wrong. After few times, the screen is cleared and it prompts for my username again and the same loop goes on.
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I quit and restarted Minecraft because it was being slow/lagging a lot to see if it would help.  Unfortunately, when I opened it up I was logged out and every time I try to login it gives me this message:     Username or password incorrect!   So, I re-typed everything and made sure to type it all correctly and it still won't let me log in. I also noticed that as soon as I hit login the password becomes blank.   I have purchased the game so it's not like a trial has expired or anything like that. What can I do to fix this?
41176
After I enable multiple sign-in, and login to multiple accounts, I see that one of them says "(Default)". How do I change which of the accounts is the default one?
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If I enter my password correct first time, I login as normal.  If I enter my password wrong, it says invalid password. If I attempt to enter the correct password now then the screen freezes and doesn't go to dock as normal. I must restart using a physical button or shutdown to get out. Login works normally after restart, assuming I get it right first time.  EDIT:  After entering a wrong password, if I click cancel and then go back to my user to login, it works fine.