HI = Human Interface
It is a large framework for Carbon based User Interfaces, like windows and their contents - handling user input events ( tracking cursors ). Carbon is the primary framework Logic is built upon AFAIK. Additionally, virtually every retail AU is Carbon based ( vs. Cocoa or Java ) for the UI - because it is native and usually much easier to move amongst platforms or plugin formats ( VST... ).
What it means...
Somebody did not handle an User event or draw properly, directly or indirectly. Since plugs are applications hosted by Logic, nearly any plugin ( esp. one that was handling events ) could cause this and it would look like Logic was crashing when aan AU could be causing Logic to crash.
To troubleshoot, disable AUs. How frequent are your crashes? Are your plugs all up to date? Note which 3rd party plugs are used in sessions which crash like so. This result is most often from a AU.
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