Tekla : Import Modified Custom Component

In this video, I explained the steps to import the modified custom component to retain the existing components in the model.
Do you know why the custom components disappear from the model?
If not watch this video.
I have covered this topic in my training : Beyond Basics : A professional guide to Tekla Structures.
Link to enrol
Beyond Basics : A Professional guide to Tekla Structures academy.ibimco...
Seamless Connection in Tekla : From Simple To Complex
academy.ibimco...