The Department of Homeland Security’s
U.S. Computer Emergency Readiness Team 
issued an urgent action recommending Windows users to uninstall the
QuickTime software as new vulnerabilities have been discovered in the software that
Apple does not plan to patch. So, Apple is deprecating QuickTime for Microsoft
Windows and will no longer be providing security updates for QuickTime on
Windows and recommend users to uninstall it whereas QuickTime for Mac is unaffected.
The Department of Homeland Security's U.S. Computer Emergency Readiness Team issued an urgent action recommending Windows users to uninstall the QuickTime software
According to Trend Micro,
during its Zero Day Initiative discovered two critical vulnerabilities
that could affect QuickTime for Windows users, ZDI-16-241 and ZDI-16-242. “And because Apple is no
longer providing security updates for QuickTime on Windows, these
vulnerabilities are never going to be patched.”
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.
The only mitigation available is to uninstall QuickTime for Windows
You can find information on how to
uninstall Apple QuickTime for Windows from the Apple website here: Uninstall QuickTime