Mac mini 2009 on 10.6.8 - what are my upgrade options

I have a Mini late-2009 running El Capitan 10.11.6 - I believe that must be the last version of the OS that supports this hardware. I did replace my internal Hard Drive with an SSD and the system is still very functional.

Back up your data, check your applications for compatibility, and download El Capitan.

(180760)

Are you sure it is Mac mini Early or Late 2009 which should both have Intel Core 2 Duo and which are limited to OS X 10.11?

Or is it Mac mini Early 2006 with Intel Core Solo which is limited to OS X 10.6?

https://en.wikipedia.org/wiki/Mac_Mini

I recently installed El Capitan on VMware. As an old habit I first tried to download El Capitan from the App Store's Purchased tab when running OS X 10.6.8 Server VM but it has been removed from there for some reason. So I downloaded the .pkg version. It opened OK in Mojave VM (VM bypasses the system check. I also have an old Mac mini 2009 but I did it this way) and the "real" installer was put in the Applications folder and I could use that to install OS X 10.11 from scratch. I didn't try the .pkg in OS X 10.6.8.

Have you tried to launch the .pkg in safe-mode?

I'd leave it like that. OS X 10.6 was a great system because it still allowed old PowerPC applications run in Rosetta emulation. I still occasionally use the OS X 10.6.8 server version via VMware fusion in Mojave/Catalina to run MT-NewsWatcher 3.5.3b3.

I recently tried to decide which other old OS X version would be the best to run other old 32-bit apps in Catalina via VMware Fusion. OS X 10.6 can run Adobe Photoshop CS6, QuickTime Player Pro 7 and MPEG Streamclip. But Adobe Lightroom 6.14 needs at least OS X 10.10-10.11 so I installed OS X 10.11 VM to test whether that is enough for my occasional use. I considered also OS X 10.14 for this task but MPEG Streamclip is not fully compatible with it and Mojave VM has some GUI artifacts because AFAIK all virtual machines lack hardware acceleration drivers (so for example the Finder and Safari tabs have the same artifacts you get when running Mojave in safe mode on a real Mac).