I'm on a upgraded version of Kubuntu, from 16.04 to 17.04 and then to 17.10.

When trying to type something in krunner or in a search field of the application menu - the letters just don't appear as typed.

Sometimes letters appear after having typed them several times.
But neither Konsole or Browser, or even text editors are affected, only search fields in krunner and the application menu.

Update: After some time (and several updates) more input fields started to misbehave:

  • password entry field in network manager
  • search in application launcher

System details:

Lenovo X1 Carbon Gen 3

Output of qtdiag:

Qt 5.9.1 (x86_64-little_endian-lp64 shared (dynamic) release build; by GCC 7.2.0) on "xcb" 
OS: Ubuntu 17.10 [linux version 4.13.0-32-generic]

Architecture: x86_64; features: SSE2 SSE3 SSSE3 SSE4.1 SSE4.2 AVX AVX2 RTM HLE



Library info:
  PrefixPath: /usr
  DocumentationPath: /usr/share/qt5/doc
  HeadersPath: /usr/include/x86_64-linux-gnu/qt5
  LibrariesPath: /usr/lib/x86_64-linux-gnu
  LibraryExecutablesPath: /usr/lib/x86_64-linux-gnu/qt5/libexec
  BinariesPath: /usr/lib/x86_64-linux-gnu/qt5/bin
  PluginsPath: /usr/lib/x86_64-linux-gnu/qt5/plugins
  ImportsPath: /usr/lib/x86_64-linux-gnu/qt5/imports
  Qml2ImportsPath: /usr/lib/x86_64-linux-gnu/qt5/qml
  ArchDataPath: /usr/lib/x86_64-linux-gnu/qt5
  DataPath: /usr/share/qt5
  TranslationsPath: /usr/share/qt5/translations
  ExamplesPath: /usr/lib/x86_64-linux-gnu/qt5/examples
  TestsPath: /usr/tests
  SettingsPath: /etc/xdg

Standard paths [*...* denote writable entry]:
  DesktopLocation: "Desktop" */home/USERNAME/Desktop*
  DocumentsLocation: "Documents" */home/USERNAME/Documents*
  FontsLocation: "Fonts" */home/USERNAME/.local/share/fonts* /home/USERNAME/.fonts
  ApplicationsLocation: "Applications" */home/USERNAME/.local/share/applications* /usr/share/usr/share/xsessions/plasma/applications /usr/local/share/applications /usr/share/applications /var/lib/snapd/desktop/applications
  MusicLocation: "Music" */home/USERNAME/Music*
  MoviesLocation: "Movies" */home/USERNAME/Videos*
  PicturesLocation: "Pictures" */home/USERNAME/Pictures*
  TempLocation: "Temporary Directory" */tmp*
  HomeLocation: "Home" */home/USERNAME*
  AppLocalDataLocation: "Application Data" */home/USERNAME/.local/share/QtProject/qtdiag* /usr/share/usr/share/xsessions/plasma/QtProject/qtdiag /usr/local/share/QtProject/qtdiag /usr/share/QtProject/qtdiag /var/lib/snapd/desktop/QtProject/qtdiag
  CacheLocation: "Cache" */home/USERNAME/.cache/QtProject/qtdiag*
  GenericDataLocation: "Shared Data" */home/USERNAME/.local/share* /usr/share/usr/share/xsessions/plasma /usr/local/share /usr/share /var/lib/snapd/desktop
  RuntimeLocation: "Runtime" */run/user/1000*
  ConfigLocation: "Configuration" */home/USERNAME/.config* /etc/xdg/xdg-/usr/share/xsessions/plasma /etc/xdg/xdg-/usr/share/xsessions/plasma /etc/xdg /usr/share/kubuntu-default-settings/kf5-settings
  DownloadLocation: "Download" */home/USERNAME/Downloads*
  GenericCacheLocation: "Shared Cache" */home/USERNAME/.cache*
  GenericConfigLocation: "Shared Configuration" */home/USERNAME/.config* /etc/xdg/xdg-/usr/share/xsessions/plasma /etc/xdg/xdg-/usr/share/xsessions/plasma /etc/xdg /usr/share/kubuntu-default-settings/kf5-settings
  AppDataLocation: "Application Data" */home/USERNAME/.local/share/QtProject/qtdiag* /usr/share/usr/share/xsessions/plasma/QtProject/qtdiag /usr/local/share/QtProject/qtdiag /usr/share/QtProject/qtdiag /var/lib/snapd/desktop/QtProject/qtdiag
  AppConfigLocation: "Application Configuration" */home/USERNAME/.config/QtProject/qtdiag* /etc/xdg/xdg-/usr/share/xsessions/plasma/QtProject/qtdiag /etc/xdg/xdg-/usr/share/xsessions/plasma/QtProject/qtdiag /etc/xdg/QtProject/qtdiag /usr/share/kubuntu-default-settings/kf5-settings/QtProject/qtdiag

File selectors (increasing order of precedence):
  en_US unix linux ubuntu

  Using "OpenSSL 1.0.2g  1 Mar 2016", version: 0x1000207f

Platform capabilities: ThreadedPixmaps OpenGL WindowMasks MultipleWindows ForeignWindows NonFullScreenWindows NativeWidgets WindowManagement SyncState RasterGLSurface SwitchableWidgetComposition

Style hints:
  mouseDoubleClickInterval: 300
  mousePressAndHoldInterval: 800
  startDragDistance: 4
  startDragTime: 300
  startDragVelocity: 0
  keyboardInputInterval: 400
  keyboardAutoRepeatRate: 30
  cursorFlashTime: 1000
  showIsFullScreen: 0
  showIsMaximized: 0
  passwordMaskDelay: 0
  passwordMaskCharacter: U+25CF
  fontSmoothingGamma: 1.7
  useRtlExtensions: 0
  setFocusOnTouchRelease: 0
  tabFocusBehavior: Qt::TabFocusBehavior(TabFocusAllControls) 
  singleClickActivation: 0

Additional style hints (QPlatformIntegration):
  ReplayMousePressOutsidePopup: 0

  Platforms requested : kde,generic
            available : kde,gtk3
  Styles requested    : oxygen,breeze,fusion,windows
         available    : Breeze,Oxygen,Windows,Fusion
  Icon theme          : breeze, hicolor from /home/USERNAME/.icons,/usr/share/icons
  System font         : "Noto Sans" 12

  General font : "Noto Sans" 12
  Fixed font   : "Hack" 9
  Title font   : "Noto Sans" 12
  Smallest font: "Noto Sans" 8

  WindowText: #ff31363b
  Button: #ffeff0f1
  Light: #ffffffff
  Midlight: #fff7f7f8
  Dark: #ff888e93
  Mid: #ffc4c9cd
  Text: #ff31363b
  BrightText: #ffffffff
  ButtonText: #ff31363b
  Base: #fffcfcfc
  Window: #ffeff0f1
  Shadow: #ff474a4c
  Highlight: #ff3daee9
  HighlightedText: #ffeff0f1
  Link: #ff2980b9
  LinkVisited: #ff7f8c8d
  AlternateBase: #ffeff0f1
  NoRole: #ff000000
  ToolTipBase: #ff31363b
  ToolTipText: #ffeff0f1

Screens: 1, High DPI scaling: inactive
# 0 "eDP-1" Depth: 24 Primary: yes
  Serial number: 
  Geometry: 2560x1440+0+0 Available: 2560x1384+0+0
  Physical size: 310x170 mm  Refresh: 59 Hz Power state: 0
  Physical DPI: 209.755,215.153 Logical DPI: 120,120 Subpixel_None
  DevicePixelRatio: 1 Pixel density: 2
  Primary orientation: 2 Orientation: 2 Native orientation: 0 OrientationUpdateMask: 0

Touch devices: 1
  TouchPad "SynPS/2 Synaptics TouchPad", max 1 touch points, capabilities: Pressure MouseEmulation

LibGL Vendor: Intel Open Source Technology Center
Renderer: Mesa DRI Intel(R) HD Graphics 520 (Skylake GT2) 
Version: 3.0 Mesa 17.2.8
Shading language: 1.30
Format: Version: 3.0 Profile: 0 Swap behavior: 0 Buffer size (RGB): 8,8,8

  • Please tell us about the computer, brand name and model, graphics chip/card name and model, RAM (size). It will help us help you. Also, if you try Kubuntu (booted from a USB drive or DVD disk), will you have the same problem? Maybe it is due to some mismatch because of the upgrading, and works better in a fresh installation (which might be tested live).
    – sudodus
    Commented Feb 22, 2018 at 10:13
  • Added to the question. Commented Feb 22, 2018 at 10:32

1 Answer 1


The Lenovo X1 carbon gen 3 computer should have enough horsepower to run Kubuntu :-)

I suspect some mismatch because of the upgrading. Please try a live system, and if it works well, backup your personal files and make a fresh installation.

See the following link (and links from it),

Try Ubuntu (Kubuntu, Lubuntu, Xubuntu, ...) before installing it


If you have problems starting from the 16.04.3 iso file (maybe appearing after update & upgrade), you can try starting from the 16.04.1 iso file, that you find via this link (scroll down ...),


When you start from the 16.04.1 iso file, the kernel will stay within the linux 4.4 kernel series, the 'xenial kernel'.

You can also try the newest version, 17.10.1 from


or the still developing 'bionic' version, to be released as the next version with long time support in April 2018. This may work well, but it is a bit adventurous because many things are still in the development phase and there may be temporary bugs.

Kubuntu Desktop amd64 testcases in Bionic Daily of the QA-tracker

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