Gatekeeper and Clam Xav

I downloaded Clam Xav a while ago and at the time it was freeware. I have been able to scan manually, but when I try to launch Clam Xav sentry (which I assume will automatically protect all the time) it says I need to enter my password to enable the sentry program to make changes. i enter the password and it keeps going back to the same prompt asking for the password again. Could this be because of Gatekeeper preventing the launch?

Gatekeeper will not prevent ClamXav from launching once it's been installed. It's possible that if you have not paid for (obtained a license) for ClamXav, that it is limited in what it can do. You probably should direct this to their support. LINK

No mention of versions being used here, OS X or ClamXav, but regardless ClamXav went commercial some time ago and it won't work or update properly unless paid for as chscag mentioned. And as suggested, check their site.

If you were thinking of using it for any malware and are using OS X 10.7.x or later, I'd strongly suggest the better and free AdwareMedic which now has been replaced with a replacement and download it from https://www.malwarebytes.org/antimalware/mac/

PS: From a recent ClamXav update notice:
"Any version of ClamXav earlier than version 2.8 will no longer receive our additional Mac-specific malware definition updates.

If you use ClamXav Sentry, and you're on OS X 10.6, it may ask for your password when you run this update. …"

You're all so knowledgable and this forum is helpful for a guy like me who doesn't have the patience to sort through ever-changing technology. Yes, I am still on OSX10.6.8 and the version of ClamXav I had is earlier than version 2.8 and, it was free so I think the sentry feature had issues. I'm now trying a 30 day free trial of ClamXav 2.8.9 and the sentry component does work. So at least I know it wasn't Gatekeeper. Through Mac forums, I'm also under the impression that ClamXav may not be the best option--it has found a few problems over the years and that gives me peace of mind, but the infected files might have been fairly harmless, I don't know. At any rate, better safe than sorry so I'll look into AdwareMedic too. Also looked into Malware Bytes, but the freeware isn't backward compatible w/ OSX10.6.

The bottom line here of course is you don't need either of them in the first place. Despite your outdated operating system there are still and never have been any Mac platform virus'. Neither Gatekeeper or ClamXav will save you from security breaches from hackers looking to access your personal information. Gatekeeper is only as good at protecting you from Malware as it's latest update which is no longer provided/supported by Apple for OSX 10.6.