Software only supported up to 10.10 but runs fine on partition???

[minvoyager]

Google Nik software is only supported up to macOS 10.10. I installed it on a partition that is a bootable 10.10 installation, and booted the software from that external partition while running the Mac using 10.12. With that arrangement, it seems to run fine on 10.12 when I go to the Applications folder on the 10.10 external partition and boot the program from there.

Is this a viable method to run software that is not intended to run on a certain OS, i.e. install its usable OS on an external partition, and then run it off that external partition, while the main OS is running in the overall computer?

 

[organicCPU]

Is this a viable method to run software that is not intended to run on a certain OS, i.e. install its usable OS on an external partition, and then run it off that external partition, while the main OS is running in the overall computer?

No.

If an application can't run on a specific macOS version, this won't work. In your case Nik Collection 1.2.11 is able to run on macOS Sierra and the description of requirements that mentions Mac® OS X 10.7.5 to 10.10 is just outdated.

I've been installing Nik Collection on Mac OS X El Capitan 10.11 without any problems. Then upgraded to macOS Sierra and all apps of the Nik Collection are still running fine as standalone apps as well as Adobe Photoshop Plug-ins (in my case Adobe CS6). Means, there is no need to install Nik Collection on a 10.10. partition. Just install it on your Sierra partition and it should work.