λ DLL Errors
qt5core.dll is missing — How to fix it on Windows 11 (2026)
If Windows shows you "qt5core.dll is missing from your computer" when you launch programs like OBS Studio, qBittorrent, the file qt5core.dll is part of the Qt 5 runtime and is almost always fixed by reinstalling that package. This guide walks you through the safe fixes — in the right order.
- Time
- 10 min
- Difficulty
- easy
- Applies to
- Windows 11, Windows 10
- Updated
- May 25, 2026
Error message
The program can't start because qt5core.dll is missing from your computer. Try reinstalling the program to fix this problem.
Symptoms
- ▸Error popup: "The program can't start because qt5core.dll is missing from your computer. Try reinstallin…"
- ▸OBS Studio refuses to launch and immediately closes
- ▸Event Viewer logs "Faulting module name: qt5core.dll"
- ▸Reinstalling the program does not fix the error on its own
Likely causes
- ▸The Qt 5 runtime is not installed (or only one architecture is)
- ▸A recent Windows update or program installer corrupted qt5core.dll
- ▸Antivirus quarantined qt5core.dll as a false positive
- ▸An older program installed an obsolete copy of qt5core.dll into its folder
How to fix it — step by step
- 01
Reinstall the Qt 5 runtime
qt5core.dll ships with the Qt 5 runtime from The Qt Company. Uninstall any existing copy from
Settings → Apps, then download the latest x64 and x86 installers from the official The Qt Company site and install both. Most qt5core.dll errors stop here. - 02
Run System File Checker
Open PowerShell as Administrator and run the command below. SFC verifies and repairs protected Windows files, including most system-provided DLLs.
sfc /scannow - 03
Repair the Windows component store with DISM
If SFC reports unrepairable files, repair the underlying Windows image first, then re-run SFC.
DISM /Online /Cleanup-Image /RestoreHealth - 04
Reinstall the program that throws the error
If the error appears only when launching programs like OBS Studio, qBittorrent, that program installed its own copy of qt5core.dll into its install folder. Uninstall it through
Settings → Apps, restart Windows, then reinstall from the official source. - 05
Check for malware
Malware often masquerades as a missing DLL. Run a full scan with Windows Defender (
Windows Security → Virus & threat protection → Scan options → Full scan) before downloading any DLL from a third-party site. - 06
Last resort: restore qt5core.dll from a clean Windows install
If every other step failed, copy qt5core.dll from
C:\Windows\System32\on another Windows 11 PC of the same architecture (x64 to x64) and the same build. Never download standalone DLLs from "DLL repositories" — they are the #1 vector for adware on Windows.