Start with Fix 1 — holding Shift to disable plugins is the fastest way to diagnose most QGIS startup failures.

Fix 1 — fastest

Launch QGIS with plugins disabled

Hold Shift while clicking the QGIS shortcut in the Start menu. This starts QGIS without loading any plugins. If QGIS opens successfully, a plugin is causing the crash.

If QGIS opens with Shift held, go to Plugins → Manage and Install Plugins → Installed and disable plugins one by one to find the culprit.

Fix 2

Delete the QGIS profile

A corrupted QGIS profile (settings, plugins, cached data) can prevent startup. Delete or rename the profile folder:

cmd.exe

# Navigate to QGIS profile folder:

C:\> explorer "%APPDATA%\QGIS\QGIS3\profiles"

# Rename or delete the "default" folder

# QGIS will create a fresh profile on next launch

Deleting the profile removes your custom settings, colour schemes, and installed plugins. Your project files (.qgs/.qgz) and data are unaffected.

Fix 3

Check for error messages

Run QGIS from the command line to see any error output:

OSGeo4W Shell

# Launch QGIS LTR with verbose output:

C:\OSGeo4W> qgis-ltr.bat --nologo 2>&1

# Watch for Python errors, missing DLLs, or permission errors

# Or check the QGIS log file:

C:\> type "%APPDATA%\QGIS\QGIS3\profiles\default\qgis.log"

Fix 4

Reinstall QGIS

1
Re-run osgeo4w-setup.exe
Run the OSGeo4W installer, select Advanced Install, find the QGIS package and click the version number to switch it to "Reinstall".
2
Or do a full clean reinstall
Uninstall QGIS packages in OSGeo4W, delete %APPDATA%\QGIS\QGIS3, then reinstall. See uninstall guide.

Common errors

Specific error messages

The application was unable to start correctly (0xc000007b)

32-bit/64-bit DLL mismatch in the QGIS install

Reinstall Visual C++ Redistributable x64 from microsoft.com

Fatal error in launcher: unable to create process

Corrupted Python environment

Reinstall QGIS via OSGeo4W setup

QGIS splash screen appears then disappears

Plugin crash during initialisation

Hold Shift on launch to disable plugins

FAQ

Not opening questions

QGIS was working, then stopped opening after a Windows Update

Windows updates can replace DLL files that QGIS depends on. Try reinstalling the Visual C++ Redistributable x64, then re-run osgeo4w-setup.exe to repair the installation. If that fails, do a clean reinstall.

QGIS opens but crashes when loading a project

The project may reference a layer or plugin that is no longer available. Open QGIS first (without the project), then File → Open and open the project — QGIS will show a warning about missing layers rather than crashing. See crash guide.

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