It sounds like you imported the photos into LR CC.
You need to have LR CC convert/upgrade your LR 5 catalog. Use File->Open Catalog in LR CC and then point to your LR 5 catalog file.
Thanks, but I did not import the photos into LR CC actively. I installed LR CC and opened my 'old' catalog with LR CC. I was asked by a pop-up to confirm the up-date of the catalog, what I did. Now I do have all the keywords I created with LR5, but they are no longer linked to the correct pictures.
I would try converting the catalog again.
OK, I'll try and let you know what happened .......
It just partially worked.
To convert the catalog again, I had to delete the previously generated catalog first. Otherwise you are not able to convert it again. But this just as a side note ..
For most of the key words in the first hierarchy it worked, but some are still missing. Second hierarchy keywords are mostly not imported and third/forth hierarchy keywords are missing completely. This is pretty bad in my case, as I'm sorting e.g. all my pictures of animals or plants by using the scientific classification. This implies several levels of keywords and it would be very time consuming to go back and re-assign all these keywords.
In all the cases you must be aware that your old Lr5 is still working on your Lr5 catalog. If you have uninstall Lr5 softwe you can reinstall it.
It's not the solution you are searching for but it's better than nothing. You didn't lost all your work.
So it seems, that there is no solution for my problem. In this respect I will probably stay with LR5 and uninstall LR CC. These few new features in LR CC are not worth it, to either loose the key words or to work with 2 LR versions in parallel.
Thanks for your help!!!