I have a number of dynamic blocks which on a day to day basis work exactly how I want them but sometimes when cutting and pasting a number of them into another drawing, they revert to the first named block from the one they were actually set to.  I am assuming it is a system variable that needs changing in the receiving drawing, but for the life of me I can't find it.  Any help gratefully received.

Hello cogsy63, if you copy/paste blocks and not insert them you won't have the AutoCAD advice to inform you that they already exist in the file.Press F2 and read what is written : XXXX already exists in the file and will not be updated ).If you want to update blocks already existing in the file than you should "built" them as WBLOCKS that's to say make a file of each one ( with the good insertion point at coordinate 0,0 or 0,0,0 if 3D ) and re-insert them one by one so that you can receive the AutoCAD advice and make the choise ( or not ) to update the blocks inside the file with the incoming file that will become an updated block.