I am not sure whether it has something to do that I upgraded to SS3.0.5 from SS2.4.5.

Everythings works fine. I deleted some modules, adjusted ss-files and php-files.

But now I have got the problem everytime I run dev/build?flush=1 an empty ClassName is added the table File and all the SiteTree tables. Even if I run it multiple time in a row.

Field File.ClassName: changed to enum('','File','Image','Folder','ProfileImage','Image_Cached') character set utf8 collate utf8_general_ci default '' (from enum(\','File','Image','Folder','ProfileImage','Image_Cached') character set utf8 collate utf8_general_ci)
Field SiteTree.ClassName: changed to enum('','AdventCalender','ApplicationPage','ArticleCategory','ArticlePage','GeneralContactPage','Home','LcPage','Maid','MaidHolder','News','RentingPage','ErrorPage','RedirectorPage','Media','SiteTree','Page','VirtualPage') character set utf8 collate utf8_general_ci default '' (from enum(\','AdventCalender','ApplicationPage','ArticleCategory','ArticlePage','GeneralContactPage','Home','LcPage','Maid','MaidHolder','News','RentingPage','ErrorPage','RedirectorPage','Media','SiteTree','Page','VirtualPage') character set utf8 collate utf8_general_ci)
Field SiteTree_Live.ClassName: changed to enum('','AdventCalender','ApplicationPage','ArticleCategory','ArticlePage','GeneralContactPage','Home','LcPage','Maid','MaidHolder','News','RentingPage','ErrorPage','RedirectorPage','Media','SiteTree','Page','VirtualPage') character set utf8 collate utf8_general_ci default '' (from enum(\','AdventCalender','ApplicationPage','ArticleCategory','ArticlePage','GeneralContactPage','Home','LcPage','Maid','MaidHolder','News','RentingPage','ErrorPage','RedirectorPage','Media','SiteTree','Page','VirtualPage') character set utf8 collate utf8_general_ci)
Field SiteTree_versions.ClassName: changed to enum('','AdventCalender','ApplicationPage','ArticleCategory','ArticlePage','GeneralContactPage','Home','LcPage','Maid','MaidHolder','News','RentingPage','ErrorPage','RedirectorPage','Media','SiteTree','Page','VirtualPage') character set utf8 collate utf8_general_ci default '' (from enum(\','AdventCalender','ApplicationPage','ArticleCategory','ArticlePage','GeneralContactPage','Home','LcPage','Maid','MaidHolder','News','RentingPage','ErrorPage','RedirectorPage','Media','SiteTree','Page','VirtualPage') character set utf8 collate utf8_general_ci)

Hi Xazen,

This happens when you use a class and then lose/rename it. So you probably had something like...

class MyPage extends Page {
...
}

and removed it. I seen it a long time back... it's not really preventable, so I have a script...

UPDATE SiteTree SET ClassName='Page' WHERE ClassName='';
UPDATE SiteTree_Live SET ClassName='Page' WHERE ClassName='';
UPDATE SiteTree_versions SET ClassName='Page' WHERE ClassName='';
UPDATE File SET ClassName = 'File' WHERE ClassName = '';

Thanks this solved the problem. However I needed to change the code a bit. I did'nt get any result with ClassName='' . I used ClassName = 0 instead (since the columns where enums).

UPDATE SiteTree SET ClassName='Page' WHERE ClassName = 0;
UPDATE SiteTree_Live SET ClassName='Page' WHERE ClassName = 0;
UPDATE SiteTree_versions SET ClassName='Page' WHERE ClassName = 0;
UPDATE File SET ClassName = 'File' WHERE ClassName = 0;