Logic Pro/Express 8: Add to Loop Library may sometimes create silent loops

Issue or symptom

When you use the "Add to Loop Library" function in Logic, the resulting loop may contain only silence.
Products affected

* Logic Pro 8
* Logic Express 8

Solution

This occurs if the region from which you create the loop is using a channel strip not set to Output 1-2 on your audio interface. Reset the channel strip to Output 1-2 before adding the loop to the library.