AEC Objects Notification

[Anonymous]

I am on AutoCAD 2016. I have a question regarding a dialog box that came up for me.  

I wanted to copy three lines from one drawing (.DWG) to another.  So, in one drawing, I selected the three lines each individually (by clicking on each line individually), performed a COPYBASE, chose a reference point, then went to my other drawing and pressed Ctrl+V to perform a PASTECLIP.  AutoCAD then showed me the following dialog box:

"This application has detected a mixed version of AEC objects participating in this operation.  Newer AEC objects will be disallowed from participating in this operation."

I then pasted the three lines without issue.  

My question is: why did this dialog box come up?  I copied three lines, and successfully pasted them.  Why would Autocad give me a notification that there are AEC objects?  I guess the reason I'm asking is: I'm concerned if I try to copy/paste certain objects from this drawing, some may not paste over. 

For reference/information: This is the first time I have ever experienced this dialog box.  I exclusively use AutoCAD 2016.  Many people access our DWG files which are on a server.  I understand the dialog box may be because someone could have pasted something over that came from a program that the Civil or Structural guys use, or something. 

For more information that might be useful: in the drawing I copied the lines from, when I open the file, I get a notification saying "This DWG file was saved by an application that was not developed or licensed by Autodesk.  What do you want to do? >Continue opening DWG file >Cancel opening file".  I get this notification all the time because we use a lot of stuff from DataCad. And, I keep getting that notification from every former DataCAD file, even after I save the file in AutoCAD.  So by this point I hardly even notice when the dialog box comes up.  However, this is the first time I have ever had that "AEC Objects" dialog box come up. 

Thanks for any help

[chriscowgill7373]

its possible that someone had opened the file in 2018 and saved down to the 2013 format, which would have created newer objects and the mixed objects message.

some people have suggested copying and pasting information from the drawing to a blank drawing may help to resolve this error message.  I cant confirm this though, here where I am, we avoid mixing versions like the plague.

[RobDraw]

When copy/pasting in AutoCAD other things go along for the ride. In this case, it is most likely definitions for those AEC objects. In order to avoid the warning, you would have to properly convert the source drawing to be fully compatible with the target drawing.