Today I followed curas advice to update to 3.1.0, so I downloaded it from ultimaker.com.
Upon opening 3.1 asks me to set up a printer, although I have it all set up in 3.0.4 (which still works, just opening the old appimage), so no printer settings are take over from the previous version.
Clicking Settings -> Profiles shows a blank window [-> Screenshot] and cura closes itself upon closing the window.

The same behavior occurs on my other machine, also Kubuntu 17.10.
Starting cura from bash does not seem to produce interesting output:
~/Desktop$ ./Cura-3.1.0.AppImage
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 72: non-double matrix element
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 72: non-double matrix element
Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 80: saw unknown, expected number
WARNING: Cannot find style "org.kde.desktop" - fallback: "/tmp/.mount_1RCFz8/usr/bin/qt/qml/QtQuick/Controls/Styles/Desktop"
QObject::connect: Parentheses expected, signal MainWindow::
QObject::connect: Parentheses expected, signal MainWindow::
QObject::connect: Parentheses expected, signal MainWindow::
QObject::connect: Parentheses expected, signal MainWindow::
file:///tmp/.mount_1RCFz8/usr/bin/resources/themes/cura-light/styles.qml:197:17: QML Item: Binding loop detected for property "width"
qml: TableViewSelection: index out of range
qml: TableViewSelection: index out of range
qml: TableViewSelection: index out of range
file:///tmp/.mount_1RCFz8/usr/bin/resources/qml/Preferences/ProfilesPage.qml:217:27: Unable to assign [undefined] to QString
Attached my ~/.local/share/cura settings folder from before the update:
cura.BU.zip
Thanks for any help with this problem
Kubuntu 17.10, Appimage Cura 3.1.0 from ultimaker.com
Hi @mpsdskd, thanks for the zip file! I think this is enough for us to investigate. We will let you know when it is fixed.
I tried to solve the problem myself in a rather low tech way:
Looks like everything works for now....?
Hi @mpsdskd I have fixed this problem in the master branch. For now you can use this workaround : make sure that you have a machine activated (selected) before going to the "Preferences -> Profile" dialog.
Sorry for the inconvenience.
Okay, I have my other machine to try, but upon opening 3.1 I have no printer to select (which is the main problem).
So you want me to create a new printer?
I did that and now there is no problem opening the profile settings.
But my main problem is, that my old printer is gone in the new version.
Ah ok. I will have a look. I used your cura directory to upgrade and I could find all the printers in the top-right list, although none is selected when Cura first starts, so I thought it was just a problem with opening that dialog.

Interesting, for me there is only the newly created ultimaker 3.
Did you try it on Linux?
On Windows 10. Good point, I will try it on Linux.
You are right. It's not working on Linux somehow.
Can you confirm that my work around works for you as well?
@mpsdskd There is a problem in copying files over during the upgrade. I suggest to do the following two steps and it should work just fine:
~/.config/cura/3.1~/.local/share/cura/3.1In case you are interested, I have made a fix: https://github.com/Ultimaker/Uranium/commit/0fbb3a147a6f13ff32920079c48f260d8fe7679d
Does not fix my problem:
I removed ~/.config/cura/3.1 and ~/.local/share/cura/3.1 and started 3.1 again.
I get asked to create a new printer and my old printers and profiles are gone.
Have you also removed ~/.config/cura/3.1?
Yes
However I did not copy ~/.local/share/cura/3.0 to 3.1 as you did not tell me to.
Did you want me to do this as well?
That's weird then... I will check later. Thanks
Slightly different symptom, so this may or may not help debug:
I converted from 3.0.4 to 3.1.0, via the "Ultimaker Cura-3.1.0-win64.exe" installer downloaded 12/10/2017.
All printers came forward. All materials came forward. All customized print profiles did not.
Windows 10 Home, V1703, Build 15063.726.
Hi @mpsdskd , I will close this issue if you don't mind since it's working for you now.
Okay, I hope the next update will be easier