Convert *.mcd to *.mcdx

Hello everybody,

I am working on a project where I need to convert some files with the extension .mcd to .mcdx

I have downloaded  Mathcad 15 M030 and Mathcad prime 3.1 for this purpose and managed to convert some files while others fails due to "unexpected error".

I tried to open the failed files with Mathcad 15  to look for any hints but the files could not be opened. I should mention that these files are a bit old, created in 2003.

Could it be that they where created in an older version and includes something that Mathcad 15 do not recognize?

Maybe someone else have encountered a similar problem before and have some idea of how to solve it?

Any help is appreciated.

Thanks in advance,

Hassan