Surface disappeared, proxy entity now at border

[Keta_Engineering]

I re-opened my file this morning and a large surface was gone.  No sign of it in the prospector.

I do see its border as a proxy entity.  There's an mms file in the drawing folder.

How can I get my surface back without recreating it?

[Neilw_05 · Accepted solution]

Try searching the forum for the topic "mms". You will probably find a solution. Here is one that might help:  https://forums.autodesk.com/t5/civil-3d-forum/where-did-my-mms-files-go/m-p/6654551