Pro structure dgn file suddenly crash and then not able to open!

Hello Everyone,

I had face this issue several time and now i just want to freeze it.

while working on power-pro structure, the dgn file was suddenly crash and after trying to re-opened it the following massage shown in the pop up window and  am not able to even open it.

please help me to resolve the issue because each time this massage appears, we lost our work.

the power pro structure version is

V8i SS7 08.11.11.616

The dgn file is attached herewith

19-102-D-Supports.dgn

Regards,

Vishal