I am unable to download the macOS 10.14.6, the download gets stuck after 335.6

If you are connecting to your router using WiFi, that may be the problem, if you can try a cabled connection,

downloads should be quicker and the connection is less likely to break. Also whilst downloading minimise the

number of devices sharing your internet connection.

If you still don't have success with Software Update try the standalone download from here,

https://support.apple.com/kb/DL2010?viewlocale=en_US&locale=en_US

once downloaded double-click to install.

Don't have your Mac set for automatic updates.

Is this just this Apple download failing, or are there other issues with the network? Mail, web, large downloads, is everything else working?

Is this a Wi-Fi, or wired network, as Eau Rouge asks?

Tried a reboot?

Are there any add-on anti-virus or anti-malware or cleaning apps here? If so, try removing those per the vendors’ instructions, reboot, and trying again.

Does booting into Safe Mode allow a download of this patch?