No block appears after importing from another course

[RegisMoo]

Moodle 3.9.11 - Adaptable theme.

We imported course content from 2023 into an empty 2024 course and the content is all there, but no Mass Actions block. The block does not exist under "add a block" dropdown list. I also went to both Boost and Classic themes to check (Adaptable is a 2 column them so sometimes things get "moved" to a 3rd column which doesn't show - but that wasn't the issue.

So the block isn't available for use, and is not listed in "Add a block" -- the plugin still works great in my test courses, etc.