How to fix
Qtcore4.dll is missing error
on Windows

I received the following error message and the come through for before my computer was upgraded to Windows 10 and is still reoccurring after the upgrade:
"the program cant start because of QtCore4.dll is missing from your computer. try the reinstalling the program to fix this problem.”

QtCore4.dll is a Dynamic Link Library[ref en-1] file that belongs to Dell Application For Reinstalling Cyberlink PowerDVD DX 8.2 Software by Dell for Windows OS. DLL files allow your operating system to perform same tasks in different applications (for example, printing).

Dynamic Link Library files are shared files and exist outside of software program. Therefore, they sometimes might cause problems and come up with error messages. Numerous reasons can cause these error messages; however, Windows will show them because it cannot correctly load the.dll file and users struggle to fix the QtCore4.dll error.

QtCore4.dll errors usually occur during startup of the operating system, a startup of the application or while trying to perform a certain task. Here are few examples of different error messages related to QtCore4.dll:

QtCore4.dll not found
Cannot find C:\\Windows\\System32\\\\QtCore4.dll
This application failed to start because QtCore4.dll was not found. Re-installing the application may fix this problem
Cannot start Dell Application For Reinstalling Cyberlink PowerDVD DX 8.2 Software. A required component is missing: QtCore4.dll. Please install Dell Application For Reinstalling Cyberlink PowerDVD DX 8.2 Software again

Sometimes these issues might arise because of incorrectly shut OS or even malware[ref en-2] infection. Because the .dll is an executable file[ref en-3], just like .exe, it can be replicated or even replaced by a virus, such as a trojan or a worm.

Thus, it is essential to make sure that no malware is affecting your computer. For that purpose, you should restart your machine in Safe Mode with Networking and run robust security software, such as [rev id=“Reimage”].

If you used the computer scanner and it did not find any infections, please proceed with the following QtCore4.dll error fixes.

Fix 1. Reinstall the application related to QtCore4.dll

As we already mentioned, the QtCore4.dll file is related to Dell Application For Reinstalling Cyberlink PowerDVD DX 8.2 Software. Thus, reinstalling application might help.

• Click Start and type in Control Panel into the search box
• Go to Programs and then choose Programs and Features
• Find a QtCore4.dll-associated program (e.g., Dell Application For Reinstalling Cyberlink PowerDVD DX 8.2 Software) under the Name column
• Right-click on it, press Uninstall and follow the on-screen instructions

Fix 2. Clean your Registry entries

Sometimes various file error messages might be related to problems in Windows registry.[ref en-4] Because multiple programs share the same file, the modification of some of them might leave invalid registry keys. In such case, cleaning Registry entries can bring the best results.

We do not recommend manual Registry modification as the process is too complicated and should only be performed by IT professionals. If you are not one of them, run a [rev id=“Reimage"] Registry cleaner which will fix everything automatically.

Fix 3. Repair QtCore4.dll related errors using System File Checker

System File Checker is a built-in scanner in your Windows OS. Once run, it checks for errors connected to QtCore4.dll and attempts to download and replace it from DLL Cache in %WinDir%\\System32\\Dllcache\\.

• Click Start button and type in Command
• Hold CTRL+SHIFT and press Enter
• Command Prompt Window with a blinking cursor will open
• Type sfc /scannow and press Enter
• After the scan is complete, restart your computer

Fix 4. Manually Register QtCore4.dll file

When software that uses QtCore4.dll is installed, it should register the file automatically. In some cases, this procedure fails and users get the "QtCore4.dll not registered" error. To fix that, manually register QtCore4.dll file using Microsoft Register Server.

• Click Start button and type in Command
• Hold CTRL+SHIFT and press Enter
• The Command Prompt Window should show up
• Type in the following: regsvr32 /u QtCore4.dll. and hit Enter
• Then, type in regsvr32 /i QtCore4.dll, and press Enter again
• Close down the window and restart your computer

Fix 5. Make sure Windows is up to date

Windows should be updated automatically. In case your updates are set to be downloaded manually, follow these steps:

• Press Start button and then pick Windows Update
• Click on Check for updates 
• If updates are available, press Download
• After the the process is complete, restart your machine