CorelDRAW X6: File not opening with exception code c0000005

Hello Guys,

I have this "particular file" in cdr x6 with approx 14-15 pages that i been working on for the last 1 month without any issues.

However since 2 days its not opening with following error message but qm able to open other cdr files.

Have tried converting to .zip but did not find riffdata, moreover had already deleted backup & temp files. 

Problem signature:
Problem Event Name: APPCRASH
Application Name: CdrConv.EXE
Application Version: 16.1.0.843
Application Timestamp: 4fff82fd
Fault Module Name: CdrCore.dll
Fault Module Version: 16.1.0.843
Fault Module Timestamp: 4fff82f1
Exception Code: c0000005
Exception Offset: 001a4764
OS Version: 6.0.6002.2.2.0.768.2
Locale ID: 1033
Additional Information 1: 0741
Additional Information 2: b2c02276656564481b7406a546e6cded
Additional Information 3: 0093
Additional Information 4: 12bc141e081cefb4d41c3541c482c446

Can anyone help as a huge amount of work has been done.

Thanks