Narrative context: What exactly is Qt?.
// problem · 10 august 2026 · 1 min
Qt installation taking much longer than expected
The progress bar froze. The installer was still a download problem, not a C++ problem.
Time wasted: 2 hours
Problem
The Qt online installer froze around 50% while downloading components, with a progress bar that had given up being honest.
Environment
Windows 11
Qt 6.x
Visual Studio 2022
Symptoms
“Downloading components” with no useful error. Network activity dropped. Cancelling and retrying returned to the same percentage.
Expected
A finished kit I could compile a hello world with.
Investigation
Waited (too long). Checked disk. Googled the percentage. Looked at the Maintenance Tool cache directory.
Things I tried
Re-running the wizard without clearing cache. Selecting every extra component “while I was there”.
Root cause
A flaky download / dirty cache, plus a kit selection that fetched far more than I needed. Visual Studio’s C++ workload also has to exist or you fail later in a different way.
Solution
Closed the installer. Cleared the Qt download cache. Installed the smallest kit that can compile hello world. Added components later.
Why it worked
The wizard is a downloader with a cache. Dirty caches stall at round percentages. Extra components multiply the stall.
Lesson
Treat toolchain installation as an engineering problem with logs and caches. Install the smallest kit first. aka.ms links in Qt docs are Microsoft’s shortener.
Found something wrong?
These notes can be incomplete, or wrong in a different environment. Suggest a correction on GitHub or email me at me@t4mer.net.
// related
// til
TIL: aka.ms is actually a Microsoft domain
A tiny explanation of Microsoft's URL-shortening domain.
// learning
What exactly is Qt? A web developer's mental model
A mental model for developers who have spent most of their careers building web applications.
// problem
Discovering that my Qt UI is QML rather than Widgets
Qt Designer would not edit the screen. The file was never a .ui form.