System crashes with "a freed zone element has been modified in zone kalloc.32"

https://www.roland.com/global/support/by_product/ua-25ex/updates_drivers/

Roland doesn't seem to have drivers for macOS versions after 10.11 El Capitan - you may need to contact them to see if the drivers are compatible with 10.13 or if there is another driver they can offer.

https://support.arturia.com/hc/en-us/sections/4405740783762-MacOS-Compatibility

Arturia doesn't list any articles for macOS compatibility for versions earlier than macOS Big Sur. Are you sure it is compatible with High Sierra? Again, you may need to reach out to their support desk.

I don't believe this is a 32-bit app problem. kalloc.32 refers to a kernel memory allocation zone - this seems to be a memory leak issue causing kernel exhaustion and a follow-on kernel panic. My guess is a bad low-level driver or incompatible kext - especially if it only happens when playing music with external MIDI hardware in use.

What OS are you running? Catalina & newer cannot run 32 bit apps.

Yes, it's a pre-sized reserved kernel zone for fast allocation using kalloc.

Decent overview of kernel zones in this article on kernel panics (for those interested in such things but not interested in a deep dive into macOS Internels...) - https://eclecticlight.co/2020/08/12/how-a-kernel-zone-memory-leak-can-panic-macos/

OK, I do see kalloc.32 on my 64 bit OS.:)

I do believe you're correct about the driver.

Thanks.:)