When running Pamac for system update it starts without any problem, but not yet in half of the process its window closes.
The update process continues in background and finishes successfully but I do not have any other means to follow than the system monitor (on KDE Plasma).
Hi @tomas_52 welcome to the forum.
Unfortunately this is a known problem that as yet hasn’t been solved. The general advice on other posts here is to use the CLI version from the terminal if you need AUR support, but if not to use pacman instead.
Alternatively if you need a GUI, try Octopi.
sudo pacman -S pamac-gtk3
Tell us how it goes next time 
It’s this old issue. Notice you can start Pamac again. It will tell you that it is waiting for another package manager to close and eventually connect again with the backend process.
Notice also that trying different frontends won’t help - CLI and GUI GTK3 version lose the connection to the backend process, too. Since the issue is random it may temporarily help to switch to the GTK3 version, but the issue may reappear.
Interesting, I had not heard of it occurring with the CLI client. 
I only use the CLI to update, and Pamac has let me down so many times that I haven’t used it in ages. Pacman and Yay, on the other hand, have never let me down.
My recommendation, as always:
sudo pacman -Syu
… followed with your preferred AUR helper. pamac should be fine for (usually) comparatively short runs like this, unlike the apparent issues using it for full system upgrades, but octopi with yay as the AUR helper is not a bad choice.
I haven’t run into the crash issue, but don’t particularly want to either and had been considering installing yay. Is yay a drop in replacement and does it use the pacman.log like pamac does?
It’s not a pacman replacement, but rather an AUR helper in the form of a wrapper around pacman. Therefore, it should indeed use pacman.log.
And when updating, you should first use pacman to update the regular repositories, and then use yay for the AUR.
I made a very simple Update-Script:
cat .local/bin/update
#!/bin/bash
sudo pacman-mirrors -c DE
echo -e "\nUpdating flatpack" ; flatpak update
echo -e "\nCleanup flatpak" ; flatpak uninstall --unused --delete-data --assumeyes --noninteractive
echo -e "\nUpdating testssl" ; git -C /home/patrice/.local//testssl.sh pull https://github.com/drwetter/testssl.sh.git
echo -e "\nyt-dlp update"; yt-dlp -U
echo -e "\n\nPacman System without AUR first"; sudo pacman -Syu
echo -e "\n\nYay AUR Upgrade"; yay -Syua
The only thing I’d change would be to omit the second y in the penultimate and last lines.
That’s on purpose—I once ran into a problem when I did an update with only some of the repositories updated, so now I always do a full update.
That’s because you hadn’t updated your mirror list. The double yy doesn’t have anything to do with that.
Thanks for pointing that out; I’ve changed it.
Anyone interested in an update script might consider TopGrade:
This works well if yay is also installed alongside pacman; in this case, pamac-cli isn’t used at all. There are many advantages to using topgrade, which can be easily discovered.
sudo pacman -S topgrade
It’d be worth it just for the logo 
It seems you forgot to edit the script in your above post, though.
I meant that I fixed it locally on my end. No one uses that simple script anyway—I guess everyone has their own. I adjusted it anyway, just to be thorough.
Perhaps I should have added a note:
“Kelly McGillis not included”.