I was using the trial version, which recently ran out. Loved the software, so a couple of hours ago I purchased a standard license via download from Amazon.
Amazon sent me what appears to be a valid license key (6 groups of 4 digits). But Lightroom will not accept the key, with the exact same error message as you in your post.
I've sent Amazon an email message. Meanwhile, I have phoned Adobe Support...and I have been on hold for over an hour, without being able to speak to a live support agent. Your phone sucks, Adobe.
I wonder if something's gone wrong with their licensing/validation system.
I never got through to phone support, but I did get support via Chat. The first support tech had to elevate it to a superior. The level 2 support tech told me to: 1) uninstall version 5.5, and 2) download and install 5.6.
The 5.6 serial number and activation experience is completely different from 5.5, and this time it took my serial number OK.
Here's the link for 5.6 if you'd like to try this...it worked for me.
I am using a Mac with Lion. I bought the subscription for $120/year and paid for a year. I bought two new Canon 7D Mark II cameras for my wife and me, and LR 5.7 is required to work with these images. I downloaded the new version but Adobe doesn't recognize the serial number I have entered. I took the serial number directly from my account information when I logged in to Adobe. I have been on hold for a half-hour (predicted time was 11-16 minutes) and am listening to that awful music. Extremely frustrating.
Our photography teacher updated her software yesterday without a hitch and came here to help us, but without any luck. Our lesson is normally two hours and, so far, we have wasted one hour and 42 minutes of her time.
We don't see any solutions to the problem, and the Chat Line is closed, for some reason.
If you are on the subscription plan, and Lightroom is requesting a serial number, then you have downloaded the wrong version. The creative cloud license does not work with a serial number, but rather is tied to your Adobe account and your password. You need to uninstall Lightroom. Then log out of the Adobe application manager and log back in. Then you will be able to install Lightroom from the application manager and you should be good to go.
Uninstalling Lightroom will not affect your images or your catalog or any other user files. Once you have reinstalled from the application manager you will be able to pick up right where you left off.
I'm having exactly the same problem. Did you fix it? If you did, how?
Describe your problem from the beginning. Provide details. Lots and lots and lots of details. Be 100% clear about what version NUMBER of Lightroom you have. Quote any error messages exactly as they appear, complete, un-edited, word-for-word.
Thanks for taking the time.
The version is 5.7.1, which is the latest version of LR5, I bought it on Amazon back in2015. DOwnloaded it worked great. My MacBook crashed so I got a new MacBook. Went to Adobe website, downloaded LR5, I accessed my license key on Amazon, however when I enter it, it tells me that it's invalid (sorry I'm not at the computlet right now so i can't quote it).
So that's my problem.
Well, please do find the exact wording when you get a chance.
Usually this happens because either you aren't actually launching LR 5 (or 5.7.1), you are launching some other version of LR; or you don't have a LR 5 serial number, you are using a serial number for some other version of Lightroom.
Another possibility is that LR is asking for a serial number of a previous version of LR, because that is needed if your purchase was an upgrade from a previous version of LR.