Very strange. With no changes to anything in /etc/rc.d/rc.4 (just using the default KDM), I can log into XFCE with any user by simply clicking the blue arrow in the bottom left and selecting "XFCE". It looks like this.

@drgibbon

According to your signature and the desktop wallpaper from your screenshot I presume you're on Slackware 14.2 and not on -current. Am I right?

@jrch:
Yes, most of the other distros support boot splashes through a hook called plymouth. Using plymouth requires patching the kernel.

Slackware provides unmodified kernels and therefore does not support boot splashes. Never really did although the Salix devs gave that a whirl some years ago. That means learning to live with some of the output spew.

One way to reduce the boot output is to use the quiet boot parameter. If using Lilo add that option to the /etc/lilo.conf append section. If using GRUB, add the option to /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT. Remember to run lilo or grub-mkconfig after editing the config files. The quiet option will avoid all of the kernel output and leave only the rc.d script output, which is more calmer.

That login screen is called the display manager. A default Slackware includes xdm. There are other display managers, but all display managers support letting users log into their desired desktop environment.

A side note, traditionally the term POST means Power-On Self Test and is related to how the BIOS ensures the system is ready to hand-off the boot process to the operating system. The spew seen in Slackware is boot initialization, often called stdout for standard output.

One way to be sure is log in as root:

chown -R lovely_wife_account_name:lovely_wife_account_name /home/lovely_wife_account_name

Like this:

chown -R betty_boop:betty_boop /home/betty_boop

If the log in issues continue and if the rc.d script output still seems annoying to the lovely wife, give Salix a test spin. Salix is a Slackware derivative that adds color to the rc.d output and renders the output more eye appealing. The Salix default desktop is Xfce.

Do know that unlike the default Slackware, the Salix devs disable the root account. That is easily restored.

14.2 on the work desktop, -current on laptop.

The fact that it's working every other time has got me stumped, maybe someone more knowledgeable will have an idea.

Did you migrate your wife's home folder from another install or distribution? Can you try starting with a fresh account (e.g. run the adduser script), run xwmconfig and try on that? The fact that its user specific seems like some config . file in the home directory is incorrect... but then it still doesn't make sense why its working sometimes.

Adding quiet will stop the kernel's messages at the start of booting but once init fires up it prints quite a few messages. I noticed alienBOB had a package for adding a splash without patching the kernel (http://www.slackware.com/~alien/slackbuilds/splashy/). I have not tried to use it though and he hasn't touched it in 12 years so I have no idea if it builds on current systems.

Running xwmconfig is not needed though when using runlevel 4/graphical login manager (it's only necessary for startx).

I suppose that depends on the definition of "quite a few." :) Compared to the kernel output spew, the init output is tame. Moreso, the init output is formatted the same within each rc.d script and does not present as scary an output as kernel spew.

When the init output uses color, like in Salix, which I adapted to my Slackware systems several years ago when the idea was first used in Zenwalk, the init output seems rather tame and docile. :)

That package is 12 years old. Here is a related discussion thread from the same period.

If I were you, I would move your wife's profile out of the way and create a new, empty one. Make your wife's account the owner of this new, empty directory, and try and log in with her user account.

If that works, then there must be some mysterious problem with her profile. If it doesn't, then I'm out of inspiration.

This might be what your looking for.
edit the $HOME/.dmrc to this
then

I apologize if you don't find this helpful since it doesn't directly address your question but I'd like to point out that it might be valuable to grasp, as well as explain to your wife, that runlevel 3 is an important "safety net". Even in the situation you're in now of trying to alter how your GUI functions, you have a great fallback exactly because you do boot to an environment that very rarely ever breaks and from which one can fix anything broken. Many operating systems and even Linux distros default to the "convenience" of the GUI but rob you of the power to fix things, leaving you dependent on some rescue disk or a complete reinstall.

I don't yet understand why you don't see other users than root in your "Greeter", which is the login graphic for all the Display Managers (xdm, gdm, sddm, lightdm, and kdm and maybe more). I just login as root in Runlevel 3 and then issue "kdm" after having created any user accounts with "adduser". The very first time the Greeter is sometimes blank but after I type in the user name the first time it always shows up automatically every time after unless I type in a different user and then that becomes the default until I type in a different user name again. There is in some of the Greeters an option to show all users but that is rarely the default since it is somewhat less secure on a PC that has several users. It's no big deal on single user boxen. Perhaps if you just type in your wife's username that first time the DM/Greeter you choose will behave the same way. It's certainly worth a shot.

I know this problem seems a struggle and it is but that struggle will make you and your wife stronger and pay you back many times over with the most reliable, most secure, most low maintenance operating system out there... and.., it will be one YOU own, not some corporate crutch wielder. Learn to walk then you can learn to run. That beats being hobbled every time.

Not sure why, but that post by enorbet suddenly makes me wonder what's the numeric id of your and your wife's accounts?

...or he could just type in

...accept the initial group defaults but scroll to the collection of several commonly required groups and add those and then co=figure whatever is desired ant login with that username. If that solves the problem User Managment (eg: Kuser) allows for creation of any needed groups or addition of users to existing groups.

Note: Of course "LightOfMyLife2" is just a brownie points suggestion but any username you like can be substituted ;)

If it's any help I'm using XFCE with XDM. Nothing fancy about this setup, though I don't have any KDE packages installed.

.xsession and .xinitrc don't exist.

I do have .dmrc with content

[Desktop]
Session=xfce

And that's pretty much it. Oh, and the inittab entry changing default runlevel 3 to 4.

XDM is perhaps too basic for some people (lack of shutdown, restart buttons -- though I've seen workarounds) but it's still a decent failsafe.

Maybe its not needed for the case of using XDM or KDM but for getting slim to start an x session it seems to be necessary. At least that's what my testing confirmed and its also in the slackware docs here: https://docs.slackware.com/howtos:window_managers:slim

Anyhow I hope OP managed to figure this out. It seems that getting a graphical login to start is not the issue, possible a permissions issue or conflicting config files. A few of us suggested starting with a fresh account so hopefully there's some follow up with that.