Just booted the computer up for the first time today and an avast warning came up that said,“the last attempt to update your virus definitions was unsuccessful. To ensure you are protected try again to update your definitions now.” So I did a manual update and everything updated as it should. My question is,what could cause it not to update,I have the latest free version of avast. Thanks,its no big deal unless it persists.
internet connection hickup… avast server hickup…
Thanks for the quick response 
Nothing to worry about. Could have been a million things. Most likely your internet connection was down for a moment.
I get it occasionally on my win7 netbook when for some reason or other the wifi connection drops out.
The main thing is that avast makes you aware of the inability to update and you can do a manual update attempt (usually successful).
Keep and eye on your Wifi signal strength meter. See if its dropping out. That is if your on Wifi.
I only posted to give an example of when it may happen.
I don’t constantly monitor the wifi icon in the tray, the more regular case is having brought the netbook out of sleep mode, I leave it to its own devices to update if one is available.