Somchai Chonwattana

Hi Joseph

I just see this post, I think you may find good solution already.
Anyway, I add my recommended here for someone who may have same problem.
This come from difference model version, later the model use more specific item type for their input data.
Actually the way to solve the problem is to open dfs2 file that M21 complain about it item then change Item Type (meny edit/item..) to what M21 model required.

Regards,
Somchai.

It seem very late reply, anyway for future use.
DHI have specific tool for res1d extraction can be download from:

DHI's download page / tool
Looking the tool name "Res1d extraction tools"

https://www.mikepoweredbydhi.com/download/mike-by-dhi-tools

Regards,
Somchai.