What should I do?
Do a site search for the error message.
Look at the links to the right under "More Like This".
I did a site search and tried the first 2 suggestions, they did not help. I am pissed. This is not what i expect as a paying customer. If I have to dig forums and keep trying I do not see a difference between paid and pirated software.
If the develop module is disabled, then you have mistakenly downloaded and installed the creative cloud version of Lightroom. It's unfortunate that this happens, but it has happened to quite a few people. The solution is to uninstall that version of Lightroom, and then download and install from this website:
Thanks. I have got the installer of version 5.6 saved (Lightroom_5_LS11_win_5_6.exe), and I upgrade when the application displays a message a new version is available.
I am not sure how creative cloud version came in the way (or how can I tell which version is it from the Help > About...) but indeed I removed creative cloud and lightroom, and reinstalled version 5.6.