Input Channels are Missing
There are several reasons why channels may be missing in the Logic software. Please follow the troubleshooting guide below to find the source of the issue.
The appropriate channels should be properly highlighted in the Logic capture settings as shown below.
Enable channels under Logic's capture settings
Sometimes, channels may be hidden from view even if they are enabled under Logic's capture settings. In this case, simply click the gear icon under any of the visible channels, and click Show All Channels.
Show all channels setting
Logic Pro 8 and Logic Pro 16 can be used with USB 2.0 ports under certain limitations as described in the article below.
When used with a USB 2.0 port, Logic Pro 16 will only have 8 channels available, as opposed to having 16 channels available when used with a USB 3.0 port.