Please help !!! Unable to access GUI after update

[Stevo]

We would have seen what happened right off if the OP had mentioned that they were updating hundreds upon hundreds of packages in one go, as you do when wrecking the system.

[asqwerth]

Is this becoming an issue where machines get upgraded to buster without notice. This upgrade breaks the system (systemd-shim, lightdm, netwwork-manager, and other important packages are removed). Here is another asking for help:
viewtopic.php?f=104&t=51379#p513797

Those were self-inflicted.

Nothing to do with MX, whose repos have always used by default the specific name of the Debian release, e.g. Wheezy, Jessie, Stretch, Buster, etc, instead of by class of repo, e.g. Stable, Testing, Unstable.

[Buck Fankers]

Yes indeed I am a novice in linux
Please explain if you have that explanation. .
And yes to all your questions. ..

I'm a I little late but here it is: (from beginner to beginner)

Will use cars as explanation. You have gasoline cars and you have diesel cars. If you pour diesel into car that runs on gasoline, you will break engine.

Debian every few years, usually around 3 years, change the whole system. Say they go from gasoline to diesel. This just happened day or two ago. All libraries are being replaced with new ones. You need to replace the whole system for this. Say you want to start using diesel, you need to replace whole engine, that runs on diesel.

Which will happen soon with MX. It will be version 19. That one will be based on diesel and will use new engine.

But the one we have now, version 18, the one that broke for you, this one is based on gasoline and it still needs old engine. And this is how it will stay for next year and half, maybe two...

If you wouldn't change repositories, you would be keep getting correct libraries for your engine. But since you did change them, you essentially pour diesel into your gasoline engine and it blew up. You can't fix it, by simply changing repositories back. Engine is bad now it need to be replaced. In Linux this is easy, you need to use live MX 18, and install it again, with the option to keep your home intact (your documents, settings...) and all should be OK. Be sure to manually save somewhere safe your documents just in case on some portable HDD.

lessons learned:

- don't use PPA's this is not ubuntu based system
- keep default repositories or you will risk breaking your system
- if you see sudenly HUGE numbers of updates available, this is red flag,don't update it, check with the forum first
- while learning, use safe install practice, use MX Package Installer. If you use say DEB package, you need to know which libraries are packaged in it, or you risk mixing diesel with gasoline engine again. MXPI will keep you in safe waters.

- learn how to use EXCELLENT MX Snapshot tool. Would be perfect in this situation. Makes iso/backup of your whole system, many many here just LOVE it. There are videos available about how to use it.

Nothing bad really happened, you are just learning new stuff :-)
Welcome to the Linux world, I was intimidated first few months, then I started enjoying it. So will you, just give it a time...

[Jerry3904]

Well done!

[Mishimainizu]

This is exactly what happened to me yesterday. I fiddled with the repositories without thinking how dangerous this can be (for Linux newcomers like me), and an instant later I was offered a myriad of updates. This happened while I was also doing other things a bit in a hurry, and as soon as I pressed "Upgrade" I started to regret. The system wouldn't boot, but thanks to yesterday's snapshot MX was up and running again half an hour later Big lesson learnt!

[chandler]

Thank you all for your support and I learnt a great deal from everyone....