I recommend using the PowerClient feature of PB 2019 R3 and get rid off hassle of installing and updating desktop apps. It supports 64-bit, takes care of runtime and external DLLs, supports incremental updates, and has bunch of new security features.  https://www.appeon.com/conference/elevate-2020/live?id=288
 
By the way, we fixed the issue you mentioned in PB 2019 R3.  So even if you don’t want to use PowerClient, you should still upgrade.

Hi Dale,

Thanks for reporting this problem, we reproduced it on our end. 
You are correct about it. This issue exists since PB 12.6. Due to that the
created MSI installation package itself is a 32-bit application, if a user
specifies “C:\Program Files\...” as its installation path under 64bit OS, the
OS will redirect the installation path to "C:\Program Files (x86)\..."
automatically.

However, even though these 64 bit runtime files are installed to "C:\Program
Files (x86)\...", it won’t affect the normal use of your 64-bit PB application.
For example, accessing 64 bit ODBC data store or 64 bit registry nodes, etc. We
will consider supporting to install the 64 bit runtime files to "C:\Program
Files\..." in later versions.

Note: in PB 2019, the default installation paths of 64 bit/32 bit runtime
package in 64-bit OS are different: 
64 bit runtime package
C:\Program Files (x86)\Appeon\Shared\PowerBuilder\x64\ 
32 bit runtime package
C:\Program Files (x86)\Appeon\Shared\PowerBuilder\

But if this issue affects the actual use of your 64 bit application, please
open a new ticket with a reproducible small case. Thanks.

Regards,
Mark Lee

Hi Dale;

   I verified this morning that the 64bit MSI installer will ignore your request to install the PB 64bit run-time into the "C:\Program Files" folder and will always install the 64bit run time into the "C:\Program Files (x86)" folder instead.

  As Roland suggested, please open a support ticket for this issue. This is certainly a bug!

Regards ... Chris

The biness of the created msi.  Or, atleast how it is designed to behave.  Running an msi containing 64-bit components, when prompted for the install location,  if you specify  "C:\Progam Files\PBdll"   and click next.  The msi installs them under "C:\Progam File (x86)\PBdll".  Causing you to manually move the directory to where you want it and edit the path to reflect the change. 

Hi Dale;

   There should be a choice in the PB Packager utility between deploying a 32bit or 64bit run-time, as follows:

HTH

Regards ... Chris