Qt Installer Framework log file path configuration

Short answer

There is no supported config.xml element, environment variable, or command-line flag in Qt Installer Framework (QtIFW) that lets you set an arbitrary destination for the log file it writes itself. The framework decides the location internally — typically the installation/target directory once it exists, and the system temp directory for early-phase failures before the target directory is created.

The practical, source-free mechanism is to capture the installer's own logging output instead of relocating its log file: run the installer or maintenance tool with verbose output and redirect both streams to a path you control.

Capturing the log where you want it

On Windows:

installer.exe --verbose > D:\logs\install.log 2>&1

On Linux/macOS:

./installer --verbose 2>&1 | tee /var/log/myapp/install.log

Redirecting both stdout and stderr matters: some QtIFW messages go to stderr, and a plain > redirect will silently drop those lines. This approach works for the maintenance tool as well, which writes its own separate log during updates and uninstalls.

What is confirmed vs. assumed

Confirmed behavior: QtIFW parses verbosity flags in the installerbase binary, and verbose console output can be redirected to any writable path. The framework's own log file location is not configurable through documented metadata.

Version-sensitive assumptions: the default log file's exact name (for example InstallationLog.txt) and its default location vary across QtIFW versions. Do not hardcode a single expected filename in collection scripts. If the installer fails before creating the target directory, the file-based log may exist only in the temp directory — or not at all — which is another reason redirected console output is the more reliable artifact.

Verifying on your build

1. Run installer.exe --help (or ./installer --help) and confirm which verbosity flags your QtIFW build actually supports — flag availability differs between versions.
2. Run a test install with the redirect above and confirm the file contains QtIFW component and script log lines.
3. Separately, check both the installation directory and the OS temp directory (%TEMP% or /tmp) for recently modified .txt/.log files so you know where the framework's own log landed, in case you also want to collect it.

If you need the framework's own file too

For centralized auditing, a common pattern is a wrapper script or scheduled task that (a) runs the installer with the redirected verbose log, and (b) after completion, copies any log found in the target or temp directory to your network share. This gives you two artifacts — the full verbose stream and the framework's own log — without modifying QtIFW source. If you later build QtIFW from source anyway, patching the log path becomes an option, but it is not required for the capture workflow above.