A statement by the US Computer Security Readiness Team, which is part of the Department of Homeland Security, said the only solution was to uninstall QuickTime.
It said: ‘Computers running QuickTime for Windows will continue to work after support ends. However, using unsupported software may increase the risks from viruses and other security threats.
‘Potential negative consequences include loss of confidentiality, integrity, or availability of data, as well as damage to system resources or business assets.’
Apple has not officially announced it is no longer supporting QuickTime on Windows, but the software is described as being a ‘legacy’ tool.
While Apple has continued to update the software for Mac computers – they currently run QuickTime Player 10 – the software on Windows computers has fallen behind and the most up-to-date version is QuickTime Player 7.
Apple has previously said that the software is expected to function properly anyway on more recent versions of Windows after Windows 7.