My Mac has multiple filesystems.  Non-system partitions are formatted Case-sensitive, Journaled while past experience with Adobe has taught me that the OS partition must be formatted Case-insensitive, Journaled.  The global Applications folder and the admin account’s home dir live on OS partition.  My non-privileged account’s home dir lives on a case-sensitive partition.

I  tried to install InDesign CS6 as myself via Adobe Application Manager download.  Very early on in the process, it threw up this error:

Googling for that error code, A12E1, returned nothing useful.  I downloaded the full installation dmg, then ran the installer.  Different error:

Which is frustrating because the partition I was trying to install on is case-insensitive.  Also, the installer does not allow you to select a different partition.  I saw many complaints in various forums about this decade-old bug.

Solution: Log in as admin (home dir on case-insensitive partition), run ID6 installer from downloaded dmg, log out of admin, log back in as myself, and run ID6.  The installer checks the active user’s home partition for case-sensitivity which does not make sense since the legacy stuff lives on the case-insensitive OS partition.