Help with Installing old version of after effects

Hi,

From what you've described, it sounds like there are two separate issues:

• After Effects 26.3 is being marked as System incompatible, which is expected if your Mac doesn't meet the system requirements for that release.

• After Effects 25.6.6 recognizes that you own the app ("You already own After Effects") but doesn't actually start the installation. That behavior isn't expected and usually points to an issue with the Creative Cloud desktop app or your account entitlement rather than with After Effects itself.

A few things to check:

• Make sure you're signed in to the correct Adobe ID that has your After Effects license.

• Try signing out of the Creative Cloud desktop app, then sign back in.

• If that doesn't help, reinstall or repair the Creative Cloud desktop app, as licensing or installation data may have become corrupted.

• If you're looking for older versions, keep in mind that Creative Cloud only makes a limited number of previous versions available, so not every historical release will appear in the app.

To help narrow this down, could you let us know:

• Are you using a Creative Cloud All Apps plan or an After Effects Single App plan?

• What version of the Creative Cloud desktop app are you running?

• If you click Help > System Info in the Creative Cloud desktop app, does it show any errors or missing entitlements?

With that information, we can better determine whether this is a compatibility issue, a Creative Cloud desktop app issue, or an account entitlement problem.

Thanks,
Kevin