Hi there, I seem to get a strange behavior with 1.40 on windows concerning deallocation. Basically, I have a managed shared memory segment and I allocate several blocks of mem in it typedef boost::interprocess::managed_windows_shared_memory shared_segment; typedef boost::shared_ptr<shared_segment> shared_segment_ptr; ... shared_segment_ptr p = new shared_segment(create_only, buffername.c_str(), begin_size); ... Now I have several allocate_aligned operations: ptr = m_segment->allocate_aligned(static_cast<size_t>(rawsize), 128); Now after a while the segment will have no more room for further blocks. So I delete some of them to gain more room: m_segment->deallocate(raw.get()); (raw is an interprocess::offset_ptr) I debugged into this and there's indeed deallocation functionality called but when I try to allocate afterwards... ptr = m_segment->allocate_aligned(static_cast<size_t>(rawsize), 128); ... I get an interprocess::bad_alloc This makes me believe that either deallocate didn't do a good job or I have to do something after the deallocate() to really make it happen. I looked into the docs for this but there was nothing mentioned so I suppose deallocate() should suffice. I think fragmentation is not really a problem here. We're talking about a few >1MB blocks in a 30MB segment. Plus some administrative overhead. Any ideas what's going on here? Cheers, Stephan