Save your serial and register online to receive support and future upgrade eligibility

The app you are trying to download from the App Store is likely the current version of the cloud-centric app called simply Lightroom. Whilst it can be downloaded and used under a 7-day trial, it is only available to purchase via one of the sevral Adobe subscription plans. It is not available to purchase outright and register via serial number.

The disc you have will be for a very old version of the app that was called Lightroom (any one of versions 1 thru 6, after which that app's name was changed to Lightroom Classic and is now only available via a subscription plan), which is a totally different product to the Lightroom app you are trying to get from the App Store.

So, explain what version you have on disc, explain what you are hoping to achieve, explain what operating system you are using, and we may then be able to help.