Cornelia: What system are you on -- PC, Mac? I'm on Mac 10.6.8. I'm also experiencing the same thing with lost tone curves since upgrading today. And that includes images that I used for testing in Beta and the trial version. But upgrading today with the disc everything was hosed.
Reason for this is that whenever the image is rendered (export, print, update of preview etc.), the tone curve settings are not included, because they're not in the Develop settings of the image (see the curve panel).
Your statement regarding non-inclusion of tone curve settings is about current LR4-bug only?
...otherwise I would be very puzzled...
Yes, of course :-)
I just checked some images I imported using the LR4 trial version. I did my processing on these images last night. I upgraded this morning and those image curves did not change. But anything I've done prior to that is hosed.
If you did your curve adjustments in parametric mode, there is no bug.
Only if you switched to point curve mode, where you drag inside the graph.
Or if you switched to linear preset curve for Raw images, or medium for jpgs.
Yes, you may have missed the workaround script.
It is in this thread: http://feedback.photoshop.com/photoshop_family/topics/lr4_deleted_all_ my_tone_curve_adjustments?utm_content=reply_link&utm_medium=email&utm_ source=reply_notification#reply_8294689
Go to the last entry of Eric Bier and open all comments to his post.
If you did your curve adjustments in parametric mode, there is no bug. Only if you switched to point curve mode, where you drag inside the graph.
That must be it, since I almost always used the sliders. So for any case where I used the sliders and then also the graph they got removed?
Who wrote this fix script? Adobe?
Did you run the scipt without issue?
A PDF with instructions how-to is included.