Can't toggle Hidden Files

Hi, Since yesterday I've been unable to toggle hidden files from the View tab of the ribbons. It's unchecked and when I click on it the check mark appears for a second and disappear again.

Only change I've done recently is installed an antivirus (Bitdefender 2016), could that be the cause?

I had this problem before on Windows 8.1 before it got updated and I had to do a reinstall to fix it. I really don't wanna do it again.

File Explorer options and ribbon check mark doesn't work for me like I said. I tried the registry key editing and I get this error "Cannot edit Hidden: Error writing the value's new contents", Hidden being the key that needs to be changed.

I'm using Windows 10 btw.

@Brink Sorry. Forgot about that. The bat file failed to restart the explorer so I did it manually and when I did it was still the same. No change

@Ztruker Yes it worked. Particularly the problem was the Intrusion Detection module of bitdefender. The explanation says that the module blocks attempts to change critical files and registry entries. Disabling that made hide/show hidden files possible.

Thanks to all for your assistance.