Is there a way to open old .dtm files?

Question

I am trying to open old .dtm files created in 1995 but InRoads says it is an invalid file format. I am using Inroads V8i SelectSeries 2 Version 08.11.07.566. Any help or direction would be appreciated. 
 
 Thank you, 
 Keith

The Zen Dude · Answer

Keith, I don't know what's going on there. I have a load of DTMs from '95 and they open fine in 08.11.07.615. Maybe you could post the DTM and I can try it.

The Zen Dude · Answer

Keith, my guess is that this file is not an InRoads DTM at all. It doesn't have the correct internal header that a DTM usually has, and the guts of it don't look like a DTM. 
 Does this mean anything to you? " cajalco road tie into mead valley outlet channel " 
 Is that what this DTM represents? 
 I don't know what this file is, but could it be a DTM from some other software besides InRoads? Other software also produced DTMs in the past, but they were not "InRoads" DTMs. Are you certain that this came from InRoads? Or is the DTM extension leading you to believe that it was an InRoads file?