Try using X-refs more ( What is Xref? Why should we use it?), that way the layers from the referenced drawing won’t be copied to yours, they will still be visible, but you can easily filter them out.Note: Deleting a layer this way will delete all the Objects in this Layer, together with objects referencing it! Now just Choose the layer to be Deleted and hit OK. A window will pop up with all the layers listed.AutoCAD will want you to Select object on layer to delete or : Type in N for Name.If there are stubborn layers that still cannot be deleted use this little trick – LAYDEL in combination with NAME. You can learn more about cleaning your drawings here: 5 Ways you can Improve your AutoCAD Performance Then I just Purge everything, until all parasites are gone. After triggering it AutoCAD gives us a list of all the Objects and settings that can be deleted. When trying to delete layers the fastest way for me is to use the PURGE Command. Layers that are X-ref dependent, also cannot be deleted.As said in the image, layers 0 and Defpoints cannot be Deleted.The Current Layer cannot be Deleted, so check if that is the case.Note: Try using Zoom > Extend to see if there are objects somewhere else in the drawing that you cannot see at first. Automate CAD drawing with LISP commands to prepare AutoCAD drawings quickly. TO use it simply make sure that the layer you want to delete is not current, type LAYDEL and select an object on that layer (alternatively you can access this function through Format -> Layer Tools -> Layer Delete). Be careful though, since it will delete the layer and its contents. Also if the layer is Locked you cannot delete the objects in it. AutoCADs menu structure is held in an external text file and can contain. This is useful to delete layers we want to purge but because they might be included in some block definition we are not using anymore, the purge command can't delete them. If a layer is Frozen or it is Turned Off the objects are not Deleted. Maybe not all the objects are Deleted.There are several reasons why some layers cannot be deleted as the AutoCAD message suggests. Sometimes, even when I’ve deleted everything from the drawing I still cannot delete them! Here comes the problem, some of the layers cannot be deleted. At this point, it would be great to clean the drawing up and delete some of the unnecessary layers.
It is common to see a drawing full of hundreds of layers, especially if you are using someone else’s drawing for a base. Many times I faced the problem with deleting layers in AutoCAD.