Please note that case-sensitive formatting of hard drives on MacOS is not compatible with our products.
On macOS 10.12 Sierra (and earlier versions of OS X), the standard HFS+ / Mac OS Extended (Journaled) format is recommended.
On macOS 10.13 High Sierra and later, the Apple File System (APFS) format is recommended.
This is a bug in Native Access that has been fixed in later versions. It should give you install options rather than asking you to add the library.
In the first instance, please upgrade Native Access to the latest possible version:
https://www.native-instruments.com/en/specials/native-access-2/
You can find legacy installers here:
https://support.native-instruments.com/hc/en-us/articles/360000407909-Native-Access-Legacy-Installers-for-Older-Operating-Systems
Then please make sure to log out, exit Native Access, reboot, and log back in.
If you are continuing to have problems and are a Mac user, please try the steps in this article:
https://support.native-instruments.com/hc/en-us/articles/360016913977-Native-Access-Error-Message-Installation-Failed-Mac-
And the steps in this article under 'Additional Steps':
https://support.native-instruments.com/hc/en-us/articles/360000884238-Native-Access-Error-Path-is-invalid