Hi, the problem is solved: the bug originated from two issues: 1) int size = ss.str().size(); it is not wise to forget to send the terminating \0 of a C-string. So there are 2 solutions: int size = ss.str().size+1 or char *buf = const cast<char*>( ss.str.data() ); The first is to be prefered. Because 2.) This fragment is _bad_: MPI_Send( &size, 1, MPI_INT, w, MW::send_job_data_size, MPI_Comm(comm) ); char *buf = const_cast<char*>( ss.str().c_str() ); MPI_Send( buf , size, MPI_CHAR, w, MW::send_job_data_tag, MPI_Comm(comm) ); Why? char *buf gets initialized with the address of a temporary copy of the C-string corresponding to the stringstream ss's string. So when MPI_Send is invoked the pointer buf points to some memory that is not guaranteed to hold the expected content. So the solution is: std::stringstream ss; { Oarchive oa(ss); oa << data; } int size = ss.str().size+1 MPI_Send( &size, 1, MPI_INT, w, MW::send_job_data_size, MPI_Comm(comm) ); MPI_Send( const_cast<char*>( ss.str.c_str() ), size, MPI_CHAR, w, MW::send_job_data_tag, MPI_COMM(comm) ) The next problem is the receiving of binary_archives: Its solution is also a bit under the hood int size; MPI_Status mstatus; MPI_Recv( &size, 1, MPI_INT, 0, MW::send_job_data_size, MPI_Comm(comm), &mstatus ); char *buf = static_cast<char*>( malloc( size ) ); MPI_Recv( buf, size, MPI_CHAR, 0, MW::send_job_data_tag, MPI_Comm(comm), &mstatus ); std::string s( buf ); std::stringstream ss( s ); The problem here is the following: we receive size C-characters and try to generaterate a C++ string from it. We are using std::string s( buf ). Here lies the error: string::string( char * ) expects a C-string, that is a \0-termionated sequence of chars. If we have in buf a binary_archive, the the probability of having a \0 in some place is very high and therefore s only holds a part of the transmitted information. Better use std::string s( buf, size) to initialize a string of length size with the data buf. And that fixes the issue. Thanks to our Ph.D student Jens for help with that. Cheers, Martin