You can turn off real-time scanning but you would then be totally unprotected. Open SecurityCenter and click Virus and Spyware Protection to expand, Click real Time Scanning and click Turn Off and tell it for how long.
There isn't a way to ignore a file unless the detection is identified as a possibly unwanted program (PUP). We have been asking for that ability to be reintroduced in the home product for around 7 years and so far our pleas have fallen on deaf ears.
If something is being mistakenly identified as malicious when you know it isn't, follow the guidelines here: https://community.mcafee.com/thread/2016
But Real-Time scanning is off, yet the detection when the folder with the file in is opened is the same as when it's on.
What I'm saying is whether it's on or off, technically it's still on as everything reacts the same.
It shouldn't be happening as far as I know but Technical Support might be better to advise you on that. It's a free phone call and linked under Useful Links at the top of the page.
Is the object appearing in the Quarantine folder?