Asus X200CA laptop F2 to access BIOS
Mint 18.3
Cinnamon 3.6.7

I was messing around in BIOS changing the Boot Option list so as to run some live USBs of other distributions. I broke something. Since it's broken, I can't get screenshots to include here.

Without a USB stick inserted, the Boot Options in BIOS look like this:

ubuntu (PO: HGST HTS545050A7E680
ubuntu (PO: HGST HTS545050A7E680
Qualcom Atheros Boot

(Yes, there are two instances of the ubuntu Boot Option showing in the list)

At turn on I get the Mint logo splash screen for a few seconds and then a window saying that the session lasted less than 10 seconds and there is an error. I click the OK button which takes me to a Login screen that won't login with my password. However, that screen has a button for Actions and when I click on that the options include suspend or shut down. Select shutdown and the computer shows the Mint logo for a second and then shuts off.

With a USB stick inserted, the Boot Options are as above but with the following Options added to the bottom of the list:

UEFI Lexar USB Flash Drive
Lexar USB Flash Drive

I move UEFI Lexar USB Flash Drive to the #1 position in the Boot Options, hit F10 (Save and Exit) and the system boots from the USB with no problem (which is where I am now).

Clues as to problem and solution? If I use another computer to create a live USB of Mint 18.3 and then install that will I lose all my files? Any way to avoid or work around that?

Thanks for any help.

The only problem I can imagine is, that the boot sequence is messed up.
Try to load the optimized defaults.

Then enter the boot menu of the Bios and try to set the correct UEFI partition (boot entry).

The "session lasted less than 10 seconds" issue is a known current one, and is not related to your BIOS changes.

Please see https://www.linuxquestions.org/quest...2A-4175626390/

Thanks for the prompt reply. I am somewhat of a neophyte. Please explain "set the correct UEFI partition".

OK but the thing is I have installed every update pushed out by Mint and have never had any problems booting at all, until yesterday when I started messing around in the BIOS.

Try all entries in the boot menu of the bios.

The very recent virtualbox-guest* update caused the problem for many people like you.

Check out https://forums.linuxmint.com/viewtop...?f=47&t=266431

Thank you I will try the fix described in the thread you linked.

No luck. Same problem with all entries.

Is it possible to reinstall the OS?

Fixed. Many, many thanks. And thank you to others who offered help. Much appreciated.

What were they thinking at Mint HQ?

The update came from the Ubuntu repos, so it came as a surprise to Mint too. Admittedly, they should perhaps have considered getting rid of virtualbox-guest* from the default Mint installation back in Mint 18, rather than wait until 18.3, but they didn't know that something like this would happen. In the end though, Mint's reaction was very quick and effective.

It just so happened that you were messing around in BIOS at the same time. Don't let that put you off messing around! As long as you have good system images/backups/snapshots, then you should be able to roll the system back if things go awry. If you haven't looked at TimeShift in Mint, I would recommend it:

https://linuxmint-installation-guide...timeshift.html

@hydrurga: Thanks for the tip. I learn a new way to save myself from myself everyday

How so? I was left with a broken O/S. Fortunately, I had a live USB and was able to get online to contact this forum to find a solution. I haven't seen any notifications or fixes directly from Mint.

Through the Mint forums (which you should always have a quick look at if you come across a problem - https://forums.linuxmint.com/viewtop...?f=47&t=266431 in this case). They also quickly released an update to the mintupdate package which purged the virtualbox-guest* packages, thus effectively immunising all those who hadn't installed the VirtualBox update.