Having switched my development setup to LibreOffice 4 (from OpenOffice 3.3), the development of UNO add-ins (using Eclipse on MacOS X) fails with the exception "init registries failed, check your registry files". Why?
By switching development setup I mean that I changed the ant build files to reference the LibreOffice ure-link folder instead of the OpenOffice ure-link folder.
In LibreOffice 4 for MacOS X (maybe also in other versions or in all version of LibreOffice) the location of the offapi.rdb file has change (compared to OpenOffice). While most (all except offapi.rdb) files stayed in their position somewhere below the ure-link folder which is in /Applications/LibreOffice.app/Contents/ure-link the offapi.rdb now resides in /Applications/LibreOffice.app/Contents/MacOS/types.
Setting the correct path in the build.xml fixed the problem.
The path base-link/ure-link is now just ure-link.