I subscribed to Photoshop/Lightroom CC and shortly before the subscription period ended I bought Lightroom 6. I deleted or thought I deleted PH/LR CC before I installed LR 6 and everything worked fine after the installation. However when I opened LR 6 the next day nothing worked - the various functions were "greyed out" - and in the upper left hand corner was this note "Lightroom mobile subscription expired" and on the photo itself was another note " the file could not be found". Any help in getting me out of this morass will be greatly appreciated. Thanks.
You can't Sign In to LR 6 with the same Adobe ID you used to buy the subscription to LR CC.
That Adobe ID is TIED to the canceled subscription.
You have to create another, second, Adobe ID and use that to Sign In and then enter the serial number that was given to you.
You also didn't need to uninstall LR CC. All you needed to do was create a second Adobe ID that is not associated to with a subscription plan, Sign Out then Sign back In using the second Adobe ID.