Environment

Enterprise Developer 5.0 onwards, Windows
 

Situation

Starting region in PAC fails, with error: CASSI1434E This region cannot join PAC MYPAC because the current operating system does not match the PAC operating system.

Resolution

With a PAC region setup, the following messages may be seen at region start, in the console.log, e.g.:

210423 06205825       6100 MFDBFH1  CASSI1434E This region cannot join PAC MYPAC because the current operating system (Windows 000 32 bit)(5.0.00343 (274019) PU 16) does not match the PAC operating system (Windows 000 32

To solve, via an Enterprise Developer command prompt, the PAC can be initialized manually, specifying the PAC name and the redis location and port, e.g:
caspac -aInitPac=MYPAC -sredis,127.0.0.1:26379

Following that the first region in the PAC should be cold-started.

Now the message is not seen anymore and regions can start normally.

Article: https://portal.microfocus.com/s/article/KM000002273?language=en_US