How do I shutdown Avast?

[flipside5]

How can I shutdown avast? Most programs allow right-click and exit from the context menu. I don't want to disable the shields, I want to exit the program.

[Para-Noid]

Why do you want to exit the program. If you exit the program/software you become extremely vulnerable to attacks and/or infections.
There is no way to "exit" avast. You can, however, disable the shields. This, too, will make you an easy target for infections.
The only way to fully exit avast is to uninstall avast. 

[Pondus]

How can I shutdown avast? Most programs allow right-click and exit from the context menu. I don't want to disable the shields, I want to exit the program.

that would be to easy.... if you could do that, then malware can do it.   
you have to turn off avast selfprotection before you can disable it..... but as already asked...why?

[flipside5]

The reason I wanted to shut it down earlier today is that I was connected to the internet via my phone,  Avast was downloading an update, and I wanted to stop it. I couldn't see anywhere within the settings to stop it downloading, so I wanted it to exit completely.

Other than that, I want to control over my PC. If I want to be able to shutdown a program, I should be able to to.  I don't really feel that I should have to explain why that's the case; it just is.  But for the sake of argument, let's say I want to try an alternative to Avast. In that case it would be much better not to have two anti-malware programs running simultaneously

I'm sure this functionality was available in an earlier version of Avast. One of the ones before it started popping up advertising messages all the time. I don't agree that the ability to shutdown the program is opening the door to malware.  In just the same way that Avast pops up a warning dialogue when closing down the shields, it could pop up a warning dialogue before exiting. Additionally, Windows itself will pop up warnings if there is no anti-malware program running.

[Para-Noid]

GUI>Settings>Updates>untick the "auto-update" option.

If you disagree with shutting down a security software makes no difference in safety, try going without.
Then come running back for help with an infection. But...if you really want an infection, it's your computer.

I doubt if you will even be able to install another anti-virus while there is one installed already.
In fact I know you can't. Try installing avast while A-V-G is installed if you don't believe me.