wwhen downloading presets I must have misplaced the "Develop" file. I can not edit photos using presets or manually. Not sure what I did? It pops up "the file can not be found" on my screen???
It seems that the file you were working on in Lightroom has been moved or deleted.
So you need to reconnect the images in Lightroom from the Library Module.
Please check the following link : Adobe Lightroom - Find moved or missing files and folders
Let me know if it helps.