I have just upgraded to VM3, and everything installed correctly, including aio.
However, if i go Components / virtiemart-aio I get a error
An error has occurred.
404 Component not found
Return to Control Panel
DO I need to worry or do something else?
The 404 or other error with the aio admin menu link is OK, as discussed here so many times that we should not have to keep repeating - there is no content in the aio component, it only serves as a wrapper to upload modules & plugins. The empty shell is there to interract with Joomla's extensions updater, although sensible users would never use the auto-update as they backup first and then use the extensions manager to install any updates.