Delete that index.dat file. That may stop the loading. Lightroom will rebuild it.
Where, in which folder did you place the copied lens profile?
This where the supplied profiles are installed:
C:\Program Files\Adobe\Adobe Lightroom\Resources\LensProfiles\1.0
And this is where you must put the custom profiles:
And if you use a Macintosh, you must store the copied profile in:
Macintosh HD/Users/[your username]/Library/Application Support/Adobe/CameraRaw/LensProfiles/1.0/,
not in the default Macintosh HD/Library/Application Support/Adobe/CameraRaw/LensProfiles/1.0.
The user Library folder may be hidden however. To unhide it, open your user Home folder and choose 'Show View Options'. At the bottom is a checkbox to unhide the Library folder.
Thank you for responding!
I didn't think of looking in the roaming profile folder. That did the trick, in addition to renaming the index.dat as you said.
Lightroom is now loading the profile, but nothing changes in the photo I apply it to. Even if I pull the distortion slider all the way, left or right, nothing happens.
I have only changed the CameraRawProfile-parameter and nothing else, although I changed it throughout the file. Would you happen to know why?
Anyway, thanks again!