boost::filesystem::path p("E:"); //Will iterate only over local directory (E:\projects\iter\build)
boost::filesystem::recursive_directory_iterator end_itr;

for(boost::filesystem::recursive_directory_iterator itr(p); itr != end_itr; ++itr) {
    boost::filesystem::path currentPath = itr->path();

.
.
.

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boost::filesystem::path p("E:\\"); //Will NOT iterate at all
boost::filesystem::recursive_directory_iterator end_itr;

for(boost::filesystem::recursive_directory_iterator itr(p); itr != end_itr; ++itr) {
    boost::filesystem::path currentPath = itr->path();

.
.
.

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boost::filesystem::path p("E:\\some-dir"); //Will iterate without a problem
boost::filesystem::recursive_directory_iterator end_itr;

for(boost::filesystem::recursive_directory_iterator itr(p); itr != end_itr; ++itr) {
    boost::filesystem::path currentPath = itr->path();

.
.
.