I recently upgraded to Mac OS Big Sur 11.4 and Lightroom 5 started crashing every time I used it, so I deleted it and downloaded the latest version from Adobe. I have a license for Lr and discovered that it cannot be applied to my download. Is there a way around this, or do I have to buy the monthly subscription?
Since you have deleted Lightroom 5, there is no way to reinstall it because the installer is 32-bit and Big Sur will not run the installer. There is no standalone version of Lightroom available that you can install. Your best alternative, if you want to continue working with Lightroom, is to subscribe to the photography plan and installed Lightroom Classic. After you install it and run it for the first time you will be prompted to allow it to upgrade your catalog. You should allow this to happen. The process will create a new copy of your existing catalog with the same name except it will have a -10 added to the name. Then Lightroom Classic will start and you will be able to continue working with your images, but with a much richer set of tools than you had with Lightroom 5.