AutoCAD 2017 Unhandled Access Violation Reading 0x0008 Exception at 9ff4bcah
[SYMPTOMS]
When installing a language pack on top of an AutoCAD verticalization (Mechanical, Architectural...) already with an update, and you try to start the product of Language Packed version, AutoCAD first gives an error like this one:

and then crashes with an error similar to this one:
while the core language still works fine (for "core language" I mean the language of the initial installation).
[FIX]
It appears to be a known issue, but I haven't found any reference to the specific error, so I'm writing it here and maybe other users will save time.
You don't need to reinstall AutoCAD (that's the long solution for people with a lot of time and not many installations to manage).
The issue gets solved if the update is reinstalled after installing the Language Pack.
I am not talking about the "AutoCAD 2017 Service Pack 1". The right update to reinstall is the
AutoCAD 2017 Service Pack 1.1
that can be downloaded via subscription account (about 450 MBytes file).
After that action also the AutoCAD and its verticalizations will work properly even in the language pack version.
Of course, if you install multiple language packs, then install the update after the last one.
Hope it helps 
(I posted the same answer in the other post)
Massimo Frison
CAD R&D // PDM Admin · Hekuma GmbH