Diagnosing Qt install issues

This page is where staff can privately share info to one another. Also see published Qt troubleshooting page

Winter 2025-26 version 2025.2

  • Mid-year update to fix thread issues found in fall quarter
  • applies more vigilant process to confirm match in version number, library always performs clean install

Fall 2025 (Qt 6.9.x)

  • Required version bumped to Qt 6.9. If you have a previous Qt install, will need uninstall and reinstall.
  • Debug helpers confirmed for all Stanford collection types

Fall 2024 (Qt 6.7.x)

  • Required version bumped to Qt 6.7.2. If you have a previous Qt install, will need uninstall and reinstall.
  • Debug helpers are currently broken for std::string and HashMap/HashSet, but hopefully to be fixed soon.

Fall 2023 (Qt 6.5.x)

  • Breaking News (9/28/2023) The "desktop install" option is back for Mac and Windows! That's the one to use. instructions have been updated.
    • Custom install of components for 6.5.3 also ok. (_The Qt installer often, but not always, offers a one-stop shopping option for "Desktop install". That option was not available on the first few days of fall quarter, so we wrote our instructions to tell students to do custom install, which requires manual select the correct components. Given that process is a bit error-prone, simpler for students to use the desktop option, but if student already successfully did custom install, no need to re-install)
  • Mac install guide no longer asks students to do full Xcode install from App Store. Instead, install command-line tools only using xcode-select --install. This is much less bulky (faster download, requires less storage) and supports older macOS versions.
    • When running Qt installer, it may bark when it doesn't find the Xcode app. Just continue on with install, Qt will eventually work it out that it has the tools it needs. Also possible to reset Xcode settings using xcode-select --reset (see this stack overflow post used to troubleshoot)
  • Latest debug helpers have been updated to properly display nested collections, GridLocation, and Bit, yay!
  • Qt download too slow? Possible to use alternate mirror if run installer from command-line

Winter 2022 (Qt 6.2.x)

  • Some Windows users have been getting a compilation error with the message "cannot make directory at...". When this happens, have them move the starter files to another location (Desktop or Documents) and run it from there
  • Students on both Windows and Mac have reported a "Could not determine which make command to run" error. Have them make sure that they're opening Qt Creator and not Qt Design Studio.

All platforms

  • Cannot configure project, message No valid C++ kits found
    • Diagnosis: didn't select necessary components during Qt install
    • Fix: uninstall Qt and re-install, be sure to select correct components
  • Debugger won't start, message Unable to create a debugging engine
    • Diagnosis: did not select necessary components during Qt install? and/or debugger setting missing from kit
    • Fix: Preference -> Kits -> (default kit) -> Debugger. Set to lldb on Mac OS, gdb for mingw on Windows
    • Fix: uninstall Qt and re-install, be sure to select correct components
  • Build error, message No CS106 library found
  • Build error, message Cannot find version 2023.1 of CS106 library
  • When building CS106 library, warning Debug helper: no such path .../qtcreator/debugger
    • Diagnosis: stanfordtypes.py debug helpers could not be installed (because we have to guess path where Qt is installed and our guess was wrong)
    • Fix: manually set in Qt Settings -> Debugger -> Extra Debugging Helper to CS106/Library/stanfordtypes.py file

Mac

  • Why does Qt repeatedly ask for permission?
    • Diagnosis: MacOS >= 10.15 has much tighter permission model on projects stored in Downloads or Desktop.
    • Fix: When prompted, authorize Qt and debugger to access files.
    • Better Fix: store project folders somewhere other than Downloads/Desktop.
  • Qt installer bounces on launch, does not open
    • Diagnosis: Is installer file stored in Desktop or Downloads folder?
    • Fix: move to somewhere else (user home folder) and launch from there. (see above about permissions)
  • Debugger hangs on start
    • Diagnosis: Xcode tools missing/unconfigured
    • Fix: reset Xcode settings
  • Build error Could not resolve SDK path for 'macos' using --show-sdk-path
    • Diagnosis: Xcode.app installed but unlicensed (only applies if they did full Xcode.app install)
    • Fix: run Xcode.app once and accept license agreement
  • If project stored on directory path containing non-utf8 characters, program will fail to run under debugger
    • Diagnosis: Qt/lldb bridge communicate about program file using full path, chokes on non-utf8
    • Fix: Rename parent folder(s) or move to path that only contains utf-8 characters
  • Reminder: macOS system requirements according to Qt https://doc.qt.io/qt-6/macos.html

Linux

Windows

  • Windows QT installer says MSVCP140.dll and/or VCRUNTIME140.dll are missing. T Fix: Download the Visual C++ Redistributable for Visual Studio 2015 from https://www.microsoft.com/en-us/download/details.aspx?id=48145 May have to try both the x64 and x86 version of the exe to get one that works.
  • If Windows hardware with ARM processor: 106B toolchain doesn’t work for them (they can emulate 32-bit x86 but not 64-bit).
    • Here is Chris Gregg's document describing the process
      • Possible to streamline (it’s still complicated — Kit creation is the big one) by zipping a 32-bit library from the campus clusters for the Qt libraries. It is still a bit unwieldy, but it does the job. This could be a way to get others up to speed more quickly without going through the whole Qt Online installer.

ARM on Windows Qt using WSL Installation Guide

Thank you Daniel Chao (djchao) for writing this up!

Requirements

  • Windows 11, any edition (should also work for any architecture) ​

    Install WSL

  • Basically, follow instructions at aka.ms/wslinstall
  • Press Windows+X, then select Windows Terminal (Admin)
  • Create the dropdown in the tab bar, then click Command Prompt
  • Type wsl --install, and reboot when it tells you to ​

    Install Debian

  • As of October 2022 Ubuntu does not have recent-enough Qt binaries in the distributions, but Debian does (unfortuantely until Debian 12 goes stable we'll have to pull packages from the testing suite)
  • Open the Microsoft Store, Search Debian, then press Install ​

    Install and Configure QT

  • Open Debian, set a username and password that the student can remember (should probably be the same as their Windows or SUNet password)
  • Add the bookworm suite to aptitude:
    • echo "deb http://ftp.us.debian.org/debian bookworm main non-free contrib" | sudo tee -a /etc/apt/sources.list
  • Install some pre-requisites:
    • sudo apt install -t bookworm qtcreator qt6-base-dev
    • sudo apt install unzip build-essential wget
  • Open Qtcreator: qtcreator
  • Configure Qt
    • In Qt Creator, click Edit -> Preferences
    • In the window that opens, click Kits in the left sidebar
    • Click the Qt Versions tab, then click Add
    • Browse to Computer, then select /usr/bin/qmake6 and click Open
    • Click Apply
    • Click the Kits tab, then click Desktop (default)
    • In the bottom pane, change the following:
      • In the Qt Version section, select the version of Qt you just added, in my case Qt 6.3.1 (System)
      • In the Compiler: C section, verify GCC (C, …) is selected or change it if not
      • In the Compiler: C++ section, verify GCC (C++, …) is selected or change it if not
    • Click OK

Install and Configure CS106 Libraries

  • Create a directory (in Windows, for simplicity, you can also create this directory in Linux but file access into Linux from Windows doesn't work very well) for 106-related stuff to live; I like creating it in the student's main user directory
    • Open Explorer, click "This PC" in the left sidebar, click "Local Disk (C: )", browse to Users -> (username)
    • Click New -> Folder in the top left cornern, name it cs106b
  • In Debian, cd in to this directory
    • cd /mnt/c/Users/<STUDENT WINDOWS USERNAME>/cs106b
  • Download and unzip CS106.zip
    • wget https://web.stanford.edu/dept/cs_edu/resources/qt/CS106.zip
    • unzip CS106.zip
  • Open Qt, configure and run the CS106 project as usual
  • Copy stanfordtypes.py manually (Qt installed in this fashion is not located at the typical path, and the .pro file for the library doesn't know where to install it)
    • cd /mnt/c/Users/<STUDENT WINDOWS USERNAME>/cs106b/CS106/Library
      • (or wherever the Library src actually is)
    • sudo cp stanfordtypes.py /usr/share/qtcreator/debugger/
  • It is often the case that if you expand the Welcome project, the analyzer doesn't know where anything is; do not be alarmed, when an actual assignment/lecture example is downloaded clang appears to not have an issue.