When I installed KMPlayer x64 on Win 7 Pro, F-Secure Antivirus prevented the program from running but provided no warning about the block.
Sorry for my reply. I am only an F-Secure user (their home solutions).
One option is to transfer KMPlayer executable to F-Secure Labs:
with description about situation.
As my own feedback -> I tried to install KMPlayer x64 on Windows 7 and then to launch it (with installed F-Secure SAFE under system).
It was not possible indeed. But with disabled F-Secure SAFE or with turned off DeepGuard module - KMPlayer x64 is launched.
I am not sure does it block by F-Secure DeepGuard or its own 'protection' by KMPlayer functionality (as prevention against hooks or deeper analysis by third-party applications). Or even if KMPlayer does not expect any delays with opening and if there is certain time delay - it just not launched at all. When we run applications - F-Secure SAFE do scan/analysis on-the-fly (so, can be 'kind of delay').
// as temporary workaround - possible to exclude KMPlayer executable (https://help.f-secure.com/product.html#home/safe-windows/latest/en/task_13205052E3D44C44BA2491A55A7F818F-safe-windows-latest-en).
But it will reduce security state (in general).