When a DWG is opened in MicroStation all elements are black. All colors in the color table are black. In AutoCAD the same file displays with normal colors.
Recreate DwgDisplayColors.tbl in dwgdataProblem may be caused by a changed DwgDisplayColors.tbl in the dwgdata directory. (The dwgdata directory is the directory MS_DWGDATA points to.)
This file can be deleted when MicroStation is not running and will be recreated.
As an alternative you can copy the standard acadcolor.tbl, rename this to DwgDisplayColors.tbl and overwrite the old DwgDisplayColors.tbl with it.