What would cause me to not be able to select a path in Illustrator?

Question

I'm dealing with an issue in Illustrator CC that I haven't come across before. I've been supplied a file that I need to work with as a vector. In Illustrator itself if I hit "Crtl + Y" and go into outline mode I can see the outline of the shape but all the detail inside of it is missing. I also can't seem to select that detail on the inside of the part in either view mode.

I've checked for clipping masks and compound paths but aside from that I don't know what other settings can be applied to a shape that would "hide" the inside detail. When opening the EPS in other software the vector lines are imported (and are editable) so I know that they exist I just can't seem to work with them inside Illustrator. Where should I start looking to try and separate out these paths?

Unfortunately I am not able to post the file so hopefully that is enough of a description.

EDIT: If it helps the other program wants to attempt to rasterize the image to "retain transparency" if that might help diagnose the issue.

Answer 1

I can think only few reasons why you can't select objects in AI.

1. Check Layers, maybe some layers are locked.
2. Also go to OBJECT > UNLOCK ALL (Alt+Ctrl+2)
3. Check object grouping (maybe it is inside another group)
4. Transparency mask

Answer 2

It turns out that the object had a transparency mask (which I have never seen before) on it. Releasing this mask made the internal profiles accessible as I had planned.