Can Aperture running om Big Sure?

Use Retrocative only in an emergency, when you cannot open your Aperture libraries in Photos to get at least your photos out. I can launch Aperture with the most recent Retroactive update in a very limited way - to read the custom metadata, see the albums and smart albums, to create high resolution previews of the edited versions, so I do not lose my work in Aperture. And to repair an Aperture Library that I cannot access otherwise. It is much safer to migrate your Aperture Libraries to an application of your choice, while you are still having a system version installed that supports Aperture fully.

Retroactive is a program that removes the 32bit code in Aperture that prevents if from running in OSes that require 64bit clean code, starting with Catalina. While the website says that it works with Big Sur, I have not gotten it to work in Big Sur, even though it did work in the Big Sur beta. I am able to run Aperture 3.6 in Catalina, but some features, mostly to do with sharing with old iLife apps and creating slideshows do not work at all as that code is 32bit and is removed by Retroactive. Read up on Retroactive and if you decide to try it, you can find it here: https://github.com/cormiertyshawn895/Retroactive

No, it does not. Clean installation of latest Big Sur on external SSD. MacBook Pro16 (2019). Fresh download of Aperture from App Store. Run latest version of Retroactive 1.9. System says OK - can run Aperture.

BUT, cannot import image files from external drive. Click on import, select drive but window showing thumbnails of files to import stays blank. Trying to import from files from the boot drive does appear to work - window showing files to import with the checkboxes to select which ones to import does get populated with images.

Viewing the contents of folders in Aperture library half works. Some blocks of images appear in the browser, but there are large blank blocks. Clicking on a blank area sometimes results in the images in that block appearing - but blocks which did have images go blank. Number of items displayed shown at the bottom of the browser window is correct (i.e. number of items in the folder) and the browser window scrolls as if all the images were there - but they are not.

Tried using external drive formatted as Mac OS Extended (Journaled) and as APFS 0 makes no difference.

Same version of Aperture, same version of Retroactive, same external drives - works perfectly under Catalina with no glitches.

You can, I believe, load an old version of an operating system on a new Mac - i.e. load Catalina onto a new Mac which came with Big Sur preinstalled. I have just successfully reverted my Big Sur installation back to Catalina. The superb cataloguing and metadata functions of Aperture are just too good to lose.

Be careful. Some new Macs might have hardware that only works with Big Sur - you need a Mac model that was available before Big Sur came along. So, a MacBook Pro 16 should be OK - but check with your Apple dealer and ideally see Catalina running on the machine before purchasing it.

No it does not, it won't even run on Catalina.

And Lightroom is not the only alternative. In no particular order for you to check out:

Lightroom Classic

OnOne Photo Raw

Exposure X6

Mylio

CaptureOne

Okay, but what happens when the one you have dies? You're just pushing the decision down the road a bit...