When saving a detail, you saw an error message similar to the following: Bad DXF group (51).
This error is related to an issue with the multi-line attribute for the detail number file. Your detail likely contains a piece of text – most commonly, the detail number – that should be designated as single line text (Text) rather than multi-line text (MText).
You can fix this issue quickly by converting the MText to Text. You can do so by exploding the MText.
Select all MText entries within your detail. Then type Explode in the Command line and press Enter.
You should now be able to save your detail without issue.
Still getting the error?
If so, place a fresh Detail Template, then save the detail again.