SSAS: Troubleshooting this exception - "An unexpected error occurred (file 'mdinfo.cpp', line nnnn, function 'MDInfo::Init')"

What's this exception?

[Analysis Services Execute DDL Task] Error: Internal error: An unexpected error occurred (file 'mdinfo.cpp', line nnnn, function 'MDInfo::Init').

My guess is that it's most likely an unhandled exception from the product. I recently encountered this exception while processing index of a particular SSAS Cube using SSIS Analysis Services Processing Task. The cube did get processed in a previous step and only the process index step failed, the cube was still available for browsing minus the indexes.