This is a fairly common system error that you might encounter at some point. If you do come across this difficulty then you are likely to see an error message similar to the following:

“The application has failed to start because Qtcore4.dll was not found. As a result (application) has stopped”.

The Qtcore.dll is a library file, in common with all DLL files, which are also known by their full name of Dynamic-link library files. They are quite important for the functioning of Windows, so when they become corrupt or are deleted by mistake then numerous issues can crop up. However, the problems related to DLL files disappearing or becoming inaccessible are thankfully not too difficult to resolve.


Because Windows is very reliant on DLL files, it is not particularly difficult to replace a malfunctioning Qtcore4.dll file. The missing DLL file can be downloaded directly from Microsoft themselves, or there are numerous other sites on the Internet that enable you to download Qtcore4.dll.

However, before you attempt any file restoration, it is a good idea to use the system restore utility to see if this will correct the problem. This will reset your machine to a time before the qtcore4.dll error caused your machine to malfunction. System restore can be accessed through the Start menu, by simply typing “System Restore” into the search box.

If the system restore utility will not run correctly then you can attempt to activate safe mode. To run Windows in Safe Mode, restart your computer and press F8 (if you have Windows installed). Once you’ve reached the desktop in Safe Mode, type ‘System’ into the Start search box and press Enter once ‘System Restore’ is highlighted. You should then be able to run the system restore utility.

If this doesn’t work then you can download a DLL file and replace the errant file in Windows. However, it is a good idea before you download any DLL files and install them to your computer to do everything you can to spring clean your PC. A good first step to achieve this is download a system checking program such as PCFix, which will repair any errors in Windows and prevent and further crashing or freezing in the future. Such software is generally pretty straightforward to both download and use.

After you’ve downloaded the appropriate file, it needs to be copied to windows/system32/. Go to the Start menu, and then select ‘Run’ before typing “regsvr32 *.dll” into the box provided in order to register the Qtcore4.dll file to the Windows system.