Hmmm. Interesting.
Our posts crossed.
I renamed the v4.7.0 library, copied in my v4.6.1 library, re-installed darktable.
Ran $darktable --version
It still said v4.7.0 was installed.
Ran $darktable
It said database needed to be upgraded (I said yes)
Crashed again with segmentation fault
I used this code
echo ‘deb /repositories/graphics:/darktable/xUbuntu_23.10 - openSUSE Download /’ | sudo tee /etc/apt/sources.list.d/graphics:darktable.list
curl -fsSL https://download.opensuse.org/repositories/graphics:darktable/xUbuntu_23.10/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/graphics_darktable.gpg > /dev/null
sudo apt update
sudo apt install darktable
from this page: Install package graphics:darktable / darktable
You need to explicitely specify the version you want to install, otherwise the latest (4.7) will be installed ! See my previous post. The versions available are listet in the apt-cache policy command.
Perhaps I am misunderstanding that download page. I’m assuming that “Latest darktable release” is 4.6.1 and “Master branch” is 4.7.0.
Perhaps that is an incorrect assumption?
You can download the binary .deb and install it using dpkg or gdebi. That may be easier to manage than the repo.
Ok, I’ll repeat the whole purge exercise. Perhaps you could verify my install command syntax before I use it when I’m ready?
this is the nomenclature of the darktable development team. For apt the latest ist the version with the largest number.
The assumption is correct, but apt doesn’t know that. It just sees 4.7.x > 4.6.y.
Right. Darktable purged. Files autoremoved. library file replaced with v4.6.1.
Checked apt-cache policy darktable.
The version I want to install is given by:
4.6.1-1.1+74.1 500
500 /repositories/graphics:/darktable/xUbuntu_23.10 - openSUSE Download
So I need to form the command line command like:
— argh… can’t cut and paste this correctly from your previous post.
package name = version in angled brackets.
What would that look like for 4.6.1?
Should be
sudo apt install darktable=4.6.1-1.1+74.1
Thank you once again!
Did that and darktable --version now says 4.6.1.
That’s where I want to be.
But will it work? let’s see…
No. 
Segmentation fault.
Whatever the problem is, it seems to affect both versions which suggests it must be something wrong with my system.
Please format the commands using the single backquote symbols (`) or blocks of code/output between lines of three backquotes (```).
Thanks
Graphics Card (GPU) ? Try to start from the commandline
darktable --disable-opencl
Didn’t help, unfortunately
More info
If I run as sudo darktable it starts. But only as a completely brand new install, no prior config or library.
But does that tell us anything?
A bit of a breakthrough…
I deleted the last folder of photos that I added and darktable 4.6.1 starts normally with all my configurations settings, scripts, presets and so on.
But no images.
Getting closer…
Groan. Rebooted and restarted dt and it crashed again. Why did it start once?
Maybe submit an issue on Github with the crash log?