chromium browser will not launch on ubuntu

Ubuntu 16.04 is not supported any more, except for Expanded Security Maintenance (ESM) which is vulnerability management and patching for critical, high and medium Common Vulnerabilities and Exposures (CVEs).

What happens, when you open a terminal window and execute the commands

/usr/bin/chromium-browser --disable-gpu

or

CHROMIUM_FLAGS="--disable-gpu" /usr/bin/chromium-browser

I know it's not supported anymore. :( But there is no point in moving forward with 32b computers. Plus when 18 came out it was a train wreck of bugs. So I stayed at 16.04 and said I'll ride till the end. Some time around the new year I'll have new 64b computers and be up to date again. :) So till then I just kept it going and have not had a problem in a long time until that power went out.

$ /usr/bin/chromium-browser --disable-gpu

[28097:28097:0904/155524.177659:ERROR:gpu_init.cc(426)] Passthrough is not supported, GL is egl
Bus error

and

CHROMIUM_FLAGS="--disable-gpu" /usr/bin/chromium-browser

[32195:32195:0904/155620.967710:ERROR:sandbox_linux.cc(374)] InitializeSandbox() called with multiple threads in process gpu-process.

I have no idea, why a power-out would cause that a certain piece of software suddenly changes behaviour.
Are you sure that you did not have such message already earlier?

Which version of chromium-browser are you running?

What output do you receive for
/usr/bin/chromium-browser --version

What happens when you execute

/usr/bin/chromium-browser --use-gl=desktop --disable-software-rasterizer --enable-gpu-rasterization --enable-gpu-compositing --ignore-gpu-blocklist --enable-features=VaapiVideoDecoder,CanvasOopRasterization,VaapiVideoEncoder,Vulkan --num-raster-threads=6 --disable-gpu-sandbox --enable-crashpad

I was watching a video on Odysee when the power went out. When it came back on a few minutes later, Chromium would not start. I can only assume the power going out did it, but really have no clue, and makes no sense to me. Because it never happened before. But I thought it would be wise to say what happened in case it did have something to do with it.

 /usr/bin/chromium-browser --version
Readout is

Chromium 90.0.4430.72 Built on Ubuntu , running on Ubuntu 16.04

/usr/bin/chromium-browser --use-gl=desktop --disable-software-rasterizer --enable-gpu-rasterization --enable-gpu-compositing --ignore-gpu-blocklist --enable-features=VaapiVideoDecoder,CanvasOopRasterization,VaapiVideoEncoder,Vulkan --num-raster-threads=6 --disable-gpu-sandbox --enable-crashpad
Readout is

[24990:24990:0904/184153.899145:ERROR:gpu_init.cc(426)] Passthrough is not supported, GL is desktop
[0904/184158.287942:ERROR:process_memory_range.cc(86)] read out of range
[0904/184158.288075:ERROR:elf_image_reader.cc(602)] missing nul-terminator
[0904/184158.300398:ERROR:elf_dynamic_array_reader.h(61)] tag not found
[0904/184213.908808:ERROR:scoped_ptrace_attach.cc(37)] process not stopped
Bus error

Your version of chromium-browser is severely outdated (current version is 116.*)
A web search shows, that there was already something done in newer versions related to that "InitializeSandbox()" message https://bugs.chromium.org/p/chromium/issues/detail?id=1112159#c22 (no longer "error", but only "warning", which should not hinder running the program)

I am sorry, but I cannot help further (apart from giving the recommendation to upgrade to a supported Ubuntu release and a current version of chromium-browser).

My last ideas:
Do other web browsers (e.g. firefox) work?
You might try installing the snap environment and the snapcraft.io-version of chromium (but I am not sure whether that works on 32bit Ubuntu 16.04)

Wow, that is crazy. I had no clue Chromium never updates. What a way to drop the ball. That info solved my problem. I cloned the hard drive and then tested this. I uninstalled it and then deleted all files with its name and a few other files that were related to it. Then reinstalled the newer version and all is good. It loaded and works.
I've learned to clone and try things on the clone drive so I don't mess up things or lose anything. Plus you can try things with no worry of destroying the info on the original hard drive.
I just have to improve my bookmarks and add the addons I had and all is good.

I was using Firefox as a backup. But my bookmakers are not on that one and Firefox is a bit laggy on video play and is not as sharp-looking. Chromium does hold the lead on video playing in my eyes. That computer is my entertainment. AKA my music and video player. It's connected to my home stereo and the large video screen in the living room.

Sometimes the conversation has the answer. Thank you.