Hi ライミン,
Welcome to the forums.
In addition to Jim's excellent advice above...
When you go to record, do you select "Record Audio" (#1 on the image below) and then select "Start of song" (#2 on the image)?
If you don't have the "Record Audio" button, press CTRL+T to switch from full-screen view to standard view.
Also, do you have the latest update for BIAB? Updates are found at the URL below. To double-check your update, go to "Help | About Band In A Box" and the update will be in brackets following the version of the program [example: version 2020(709)] -- #709 is the latest update.
https://www.pgmusic.com/support_windowsupdates.htmHope that this helps,
Noel