shared_ptr does not call destructor

Hi: I am using windows 2000 with VC 6.0 and boost 1.28. In my project, I have an array of pointers to objects: class foo { public: ~foo() {} private: std::vector myArr_; }; I found that the destructor for MyType is never called. Printing the shared_ptr::use_count = 6 at ~foo() above. Any suggestions on what could be happening and how to approach the debugging? Thanks, -Ani