Has anyone considered letting Aperture live forever on a VM?

You'd have to be running Snow Leopard (10.6.x) in a virtual machine and run Aperture on that. Starting with 10.7, OS X can only be run in a virtual machine on a Mac that is running the same OS X version as the host (i.e. 10.8 vm on a 10.8 host only, 10.11 vm on a 10.11 host only, etc.) So that doesn't help people who want to run older OS versions in virtual machines unless they want to go all the way back to Snow Leopard.

You can get Snow Leopard Server from Apple for about $20. It's the only Snow Leopard version that the virtual machine companies support, and Aperture runs just fine on it.

The last version of Aperture running on Snow Leopard is Aperture 3.2.4.

If you no longer have this version installed, install the boxed version of Aperture sold on DVD, then update to 3.2.4 using the updates page: Aperture 3.2.4

There is one big problem with this early version of Aperture 3. It is still using the old Google Maps, and Aperture may crash, if you open an image in the Info panel, the will try to access Googles Maps servers.

The newer versions of Aperture 3 are using apple's maps servers and do not have that problem. But you would need to be able to run Mavericks and Aperture 3.5.1 or Aperture 3.6 on Yosemite or Mavericks.

I will keep a bootable clone of the El Capitan System I am running now with Aperture 3.6. I have been running aperture 3.4.5 from a second partition with Mountain Lion, and that worked very well.

To fix Aperture's problem with Google maps in earlier Aperture versions see this User Tip: Patching Aperture 3.4.5 to make Places work again

However, I pressed the download button on the link you provided, and it is letting me download 3.2.4.

That is an update link. You need to have an early version of Aperture 3 installed, to be able to run the updater. Do you still have a old backup of your Mac? Perhaps an old bootable clone?

One thing I'm wondering is if the library itself is backward compatible to an earlier Aperture version?

No, it is not. Aperture will only open libraries of the same versionor older versions.

Or cone your mac to an external drive (I keep bootable clones as my second backup in addition to Time Machine) and start the mac from that drive to work with Aperture, if you ever upgrade to a system version that will render it incompatible.

The advantage would be that you would not need to downgrade your Aperture library.

I used to keep a Mountain Lion clone in a second partition to be able to run Aperture 3.4.5, the last version that still had the better maps with terrain data.

I understand why you would want a virtual machine. It is so much more convenient than a dual boot system, but the advantage of a dual boot system would be, that the performance would be faster,

One problem with this is that if you get a new machine it might not be able to boot the older operating system.

But assuming VMware keeps updating for each new OS your virtual machine can live forever.

One problem with this is that if you get a new machine it might not be able to boot the older operating system.

But assuming VMware keeps updating for each new OS your virtual machine can live forever.

When I get a new machine, I keep the old one to run the old system, if it is still working. But you are right, Keith, - new hardware is equally dangerous for compatibility as new system versions. Even a firmware update could be risky.

Bu the virtual machine would require Snow and an early Aperture 3 version, and the boxed versions of Aperture at eBay or Amazon are still expensive. I don't know any free save download site.

I do see some old Aperture 3 boxed versions on Amazon - those would still work under Snow Leopard - correct?

This boxed versions will probably install Aperture 3.1 or earlier. You can update them using the Aperture 3.2.4 updater you found on the support page, and then will have the best stable version for SnowLeopard.

The only problem that you mentioned is that it may crash if going out to the old google map servers. I wonder if you can turn off that mapping feature?

Yes, first try to launch Aperture while being offline. Then disable the Places in the Aperture > Preferences > Advanced. Set "Lookup Places" to "Never".

If that should not suffice, you can remove the two HTML files from the Aperture application bundle, that are trying to contact Google. Then the java scripts will not launch, that are keeping crashing.

See this User Tip: Patching Aperture 3.4.5 to make Places work again

I looked, and as far as I can tell, the version you found is a full installer, not an upgrade.

The upgrade versions are having the word "Upgrade" in the name.

But it is still very expensive for software you already own.

I've used the dual boot method with clones to run older Apple and non-Apple deprecated software and it works OK. But it is a pain. It helps to keep the Aperture Library accessible on say your boot drive SSD for speed purposes, but often the system on the clone itself is just slower. And you've gotta maintain and back up the clone. But that's all manageable. What I wonder about is whether in future system updates the Aperture library will still be accessible from other applications as it is now; that's a big benefit of Aperture over non-Apple alternatives right now. But if every time I needed an image from Aperture that was adjusted and editing within Aperture, and had to boot into another HDD based system to get it, I'd go nuts quickly.

So maybe nice to have use of the older system, but not anywhere near a complete solution.