Ubuntu won't let me sign in.

mistermike

New Member
When I get to the first splash screen in 18.04 , it says 'unable to start session' . It doesn't recognize or accept my password.
On this dual boot (Win7/ Linux) I have tried booting from older kernels, same. At times there has been a terminal screen but I dont know the commands that might solve this 'can't start session' prob. The terminal screen is grub 2 rescue mode. What command(s) might i try when at this screen prompt, that might solve my problemo.
Or ... something else to try? ...
Is there help for this login problem?
 
Last edited:


JasKinasis

Well-Known Member
If you get to a login screen and get the unable to start session error after entering your password - it usually means that X, or the desktop session failed to load.

In which case - From the login page, you could try pressing ctrl alt F2 to go to a virtual terminal/tty.
This will ask you for your username and password and will log you into a terminal session and we can try to diagnose the problem with the session from there.

But if you’re seeing the grub rescue screen, then this doesn’t sound like a login problem. It sounds more like a boot-related problem.

Unfortunately, I’ve never dual booted, or had to fix any boot-time problems with grub. So if it's boot-related - I’m probably the wrong person for this. But somebody else here will be able to help.

But if you can get into a tty session, I can almost certainly help to diagnose the problem.
So first up, is this boot-related? Or session related?
 

Alexzee

Active Member
If you have the all black screen with the grub rescue prompt you likely need Grub repair.
This means that the Grub can't find the folder OR it's contents is missing or corrupted.


Here's another way to fix the grub rescue issue.

Do you have the Ubuntu cd/dvd or Ubuntu Live usb?
 

wizardfromoz

Super Moderator
Staff member
Gold Supporter
Do you have the Ubuntu cd/dvd or Ubuntu Live usb?
If he does, we can chroot into the install and take a look around and maybe fix it from there.



(Wizard appears in a puff of smoke, glad to be back from a 10-day internet outage)

G'day @mistermike , and welcome again :)

Another question you might answer is what you plan to do when Windows 7 support ends in 3 weeks?

Cheers

Chris Turner
wizardfromoz
 

captain-sensible

Well-Known Member
@wizardfromoz heres a thought i have regarding chroot . I once fixed ext4 filesystem of slackware (laptop) main installation partition by using fsck from knoppix usb attached to laptop .
Now recently a question came up on this site and i thought of about use of chroot, would you could do with it and waht you can't do with it.


I guess the only thing you can not do is use chroot from knoppix live usb and evoke fsck on the laptop os. To use fsck partition should not be mounted anyway ,so i guess there would be no way of doing that anyway and no point? put it did come to my mind
 

JasKinasis

Well-Known Member
@wizardfromoz heres a thought i have regarding chroot . I once fixed ext4 filesystem of slackware (laptop) main installation partition by using fsck from knoppix usb attached to laptop .
Now recently a question came up on this site and i thought of about use of chroot, would you could do with it and waht you can't do with it.


I guess the only thing you can not do is use chroot from knoppix live usb and evoke fsck on the laptop os. To use fsck partition should not be mounted anyway ,so i guess there would be no way of doing that anyway and no point? put it did come to my mind
In that case, you'd do the fsck of the HD from knoppix live first. Once fsck has done it's thing you can mount the drive, before chrooting and poking around.
 

captain-sensible

Well-Known Member
In that case, you'd do the fsck of the HD from knoppix live first. Once fsck has done it's thing you can mount the drive, before chrooting and poking around.
yes thats what i previously did and no problem using chroot, but i guess you can't evoke fsck of os on laptop from knoppix command line since its not mounted, and you can't run without possible damage fsck on a mounted partition. probably the way my brain is wired and i even haven't sampled the new purchase from "chateau Lidl" yet !
 

JasKinasis

Well-Known Member
yes thats what i previously did and no problem using chroot, but i guess you can't evoke fsck of os on laptop from knoppix command line since its not mounted, and you can't run without possible damage fsck on a mounted partition. probably the way my brain is wired and i even haven't sampled the new purchase from "chateau Lidl" yet !
I can’t speak specifically for knoppix, because I’ve never used it. But generally speaking, if you boot your laptop from any live CD/DVD/USB, then any hard drives attached to that laptop will be visible and accessible, but not mounted.

So therefore, you should be able to safely fsck your hard drives on your laptop using the terminal in the liveCD/DVD/USB environment.

Literally: boot live CD, open terminal, fsck the main HD, mount HD, chroot in, poke about and do what you need to, exit chroot, unmount HD, reboot into main HD.
 

mistermike

New Member
If you get to a login screen and get the unable to start session error after entering your password - it usually means that X, or the desktop session failed to load.

In which case - From the login page, you could try pressing ctrl alt F2 to go to a virtual terminal/tty.
This will ask you for your username and password and will log you into a terminal session and we can try to diagnose the problem with the session from there.

But if you’re seeing the grub rescue screen, then this doesn’t sound like a login problem. It sounds more like a boot-related problem.

Unfortunately, I’ve never dual booted, or had to fix any boot-time problems with grub. So if it's boot-related - I’m probably the wrong person for this. But somebody else here will be able to help.

But if you can get into a tty session, I can almost certainly help to diagnose the problem.
So first up, is this boot-related? Or session related?
 

mistermike

New Member
Thank you. I'll try the c a f2 first. I get to the login (primary screen -- mostly blank (ubuntu logo ) except wirless is enabled, password box is there. it asks please enter password... ok... i do.. then it says unable to start session. ill try getting around that with the advice from you. What i have been doing is a hard shutdown at that screen not knowing how to get out of it. frustrating. Through windows disc management, i see that my linux partion is still there, but again, cant log into...

thanks will try yours. ...soon :)
 

mistermike

New Member
If you get to a login screen and get the unable to start session error after entering your password - it usually means that X, or the desktop session failed to load.

In which case - From the login page, you could try pressing ctrl alt F2 to go to a virtual terminal/tty.
This will ask you for your username and password and will log you into a terminal session and we can try to diagnose the problem with the session from there.

But if you’re seeing the grub rescue screen, then this doesn’t sound like a login problem. It sounds more like a boot-related problem.

Unfortunately, I’ve never dual booted, or had to fix any boot-time problems with grub. So if it's boot-related - I’m probably the wrong person for this. But somebody else here will be able to help.

But if you can get into a tty session, I can almost certainly help to diagnose the problem.
So first up, is this boot-related? Or session related?
i dunno cheroot from adam. cheroot brings to mind the cigars clint eastwood used to smoke in those westerns. thats the extent of my chroot knowledge. but if you could guide me from a terminal screen that would be great. not today though but thank you vm.
 

mistermike

New Member
If you have the all black screen with the grub rescue prompt you likely need Grub repair.
This means that the Grub can't find the folder OR it's contents is missing or corrupted.


Here's another way to fix the grub rescue issue.

Do you have the Ubuntu cd/dvd or Ubuntu Live usb?
yes i have ubuntu iso but i dont want to go that deep just yet. but hold that thought!
 

mistermike

New Member
If he does, we can chroot into the install and take a look around and maybe fix it from there.



(Wizard appears in a puff of smoke, glad to be back from a 10-day internet outage)

G'day @mistermike , and welcome again :)

Another question you might answer is what you plan to do when Windows 7 support ends in 3 weeks?

Cheers

Chris Turner
wizardfromoz

i need windows for several programs that are as yet unavailable in linux. I intend to keep offline in win 7 when support ends. which will be somewhat of a nuisance. smoke getting to you over there mate? bad situ. the whole world watching the fires. very sad.
 

mistermike

New Member
If he does, we can chroot into the install and take a look around and maybe fix it from there.



(Wizard appears in a puff of smoke, glad to be back from a 10-day internet outage)

G'day @mistermike , and welcome again :)

Another question you might answer is what you plan to do when Windows 7 support ends in 3 weeks?

Cheers

Chris Turner
wizardfromoz
bit of irony there with the puff of smoke. :cool:
 

wizardfromoz

Super Moderator
Staff member
Gold Supporter
Yeah, I'm the good, the bad and the ugly all wrapped into one - ask my wife :)

Mate I'm going to be in and out a little this morning, but I'll be back in a couple of hours and can stitch together a blow by blow on chrooting.

Not invading your privacy if you don't wish to say where you are from, but a timezone would help me to have it for you for when you are bright-eyed and bushy-tailed. These timezone discrepancies can be tedious with my work here.

Tried casting a spell a couple of years ago to synchronise timezones, but the world started spinning backwards and I lost a couple of people off into the stratosphere before I got it fixed.

Cheers

Wizard

BTW if someone else comes along with a chroot plan in the meantime, by all means take their input on board.
 

mistermike

New Member
hahaha. no problem. central Canada (= central standard time) where the sky is huge.
not interested too much about cherooting tho, except for maybe when it's smoke time. Did you know pot's legal in Canada now? Wish I were younger and a little wilder, cuz it doesn't have the same appeal to me now as in my university days of the 70's. ;)
 

mistermike

New Member
hey ... while mmm here, and before i post a thread... can you tell me how to do a screengrab while in a terminal or Dos? I've been doing the camera thing.
 

mistermike

New Member
If you get to a login screen and get the unable to start session error after entering your password - it usually means that X, or the desktop session failed to load.

In which case - From the login page, you could try pressing ctrl alt F2 to go to a virtual terminal/tty.
This will ask you for your username and password and will log you into a terminal session and we can try to diagnose the problem with the session from there.

But if you’re seeing the grub rescue screen, then this doesn’t sound like a login problem. It sounds more like a boot-related problem.

Unfortunately, I’ve never dual booted, or had to fix any boot-time problems with grub. So if it's boot-related - I’m probably the wrong person for this. But somebody else here will be able to help.

But if you can get into a tty session, I can almost certainly help to diagnose the problem.
So first up, is this boot-related? Or session related?

if i knew how to do a screen capture from that screen(s) , it would make things much simpler and expedient. ???
have yet to try cn/alt/F2. I get stuck at failed to start session, so that suggest a session-related issue. We'll see . I'm ecstatic that my old HHD et al got transfered to new drive, but the caveat remains that this no-boot is still there. i.e. the problem got transferred, as i imagined it would. by sending you / this thread some screen clips will be insightful to all . i can get into the black screen grub rescue if i work at it. is that the same as a terminal you think? tks.
 

wizardfromoz

Super Moderator
Staff member
Gold Supporter
central Canada
I'm betting the one that hasn't got a natural border - Saskatchewan? Cool.

... can you tell me how to do a screengrab while in a terminal or Dos? I've been doing the camera thing.
Up right of function keys, if you have PrtScr, pressing it will capture the whole desktop.

Shift-PrtScr will grey the screen and present crosshairs for you to select the area to grab.

Ctrl-PrtScr - can't remember ... mmm beer

Alt-PrtScr - active Window

Pretty much the same as in Micro$oft.

You likely won't be able to capture the Grub Rescue screen (that I know of).

Ctrl-Alt-F2 works on many computers. Others may have a different function key, for example I am in Linux Mint 19.2 'Tina Cinnamon - and it is Ctrl-Alt-F4.

It brings you into a tty session - where tty means would you believe - teletype?

I'll bring you more soon and we'll see if we can work from that Grub Rescue screen without having to smoke a cigar.

If not, we'll go chrooting :)

Have a read of this, after reading what follows the link

https://www.linux.com/tutorials/how-rescue-non-booting-grub-2-linux/

The path we would would likely follow would be

  • first part, determining the partitions relevant, up to but not including
  • Booting From grub>
  • Your says Grub Rescue, so we pick up there through to the end.
The article is an oldie but a goldie and unlike many articles is still relevant 5 years or more on.

Back when I can.

Wiz
 

JasKinasis

Well-Known Member
If the OP can get the machine to boot to the login page
Try the following:
1. Use Ctrl+alt+F1 to access the 1st virtual terminal
- this will prompt for a username and password and should let you log-into a terminal
2. Use ctrl+alt+F7 to return to the login page
3. Attempt to log in via the login page (and I assume it will fail to start the session)
4. Switch back to the virtual terminal using ctrl+alt+F1 and you should hopefully see a bunch of error messages from your login manager, or from X - which will hopefully tell us more information about why the desktop session is failing to start.

And if you don't see any error messages, the next thing to do will be to locate the .desktop file that relates to your usual desktop session and try starting a desktop session manually. But before even thinking about any of that - First try the above steps and see what output you get.
 


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