Same for me - no Dawnguard but the same Creation Kit issue, not with all mods but with most newer or updated house mods I wanted to adjust to my likings. I am so happy I found an easy solution now and want to share it here (I found it in a post of "Nyram" at the Steam Users' Forums - many thanks to Nyram!!!): This was the relevant non-dawnguard part for me, applying also to the the SkyrimEditor.ini: "I have also read that it is necessary to add sLanguage=YOURLANGUAGEHERE to the [GENERAL] SECTION. I did this too, adding ENGLISH, but it did not do anything to correct my problem. I did read reports that it worked for other people using non-English languages." Well, for me it worked with adding sLanguage=GERMAN :-)) Miraculously the CK will open all the critical mods now! I hope some more people who could use this solution might be able to find it now.
