Can I temporarily disable avast

I have Western Digital external HD Passport Essential 2010 and need to update software to function with latest OS10 update. It requires disabling antivirus hardware.
How do I do this?

Application updates don’t require the av to be disabled, unless they have something to hide :wink:

You can temporary disable the File & Web shields. Except of them, there is nothing that could somehow interfere with any other software (update) on the machine.