i have a huge build that i made on my server and i copy it but i never pastes fully and i get error:

Exception while calling NextTick callback (InvalidCastException: Specified cast is not valid.)
at Oxide.Plugins.CopyPaste.PasteLoop (Oxide.Plugins.CopyPaste+PasteData pasteData) [0x00e24] in <ab357d1976624c3cbf0821f7246166cb>:0
at Oxide.Plugins.CopyPaste+<>c__DisplayClass44_0.<PasteLoop>b__0 () [0x00000] in <ab357d1976624c3cbf0821f7246166cb>:0
at Oxide.Core.OxideMod.OnFrame (System.Single delta) [0x00051] in <beb2b64691c64e2b95b99491bd85442c>:0

In the past, I've had that happen when there are electric string lights in the build. 

Venedas

In the past, I've had that happen when there are electric string lights in the build. 

i have same problem, except the string lights pasted over but the other side of the base was missing which have no electric string lights on it

happened to me to, I removed the deluxe Christmas lights and error was gone and base copied fine.
but dam took me a wile to figure out it was those dam lights

Were you ever able to find out which item caused the issue? We have the same problem since this wipe, so i guess it could be something from the electrical items, no christmas lights were used. :-/

Since a recent update from Facepunch on Switches, etc, it could be that which is causing the error. But, if the building is large you will want to copy it with a larger radius. Try /copy testbase radius 10

Yeah we think it's something with the electricity. Not sure which item exactly, maybe switches or branches, because those don't get deleted when you do "undo".