This problem occurs at a higher level but I've tried to strip it back. I've reproduced this problem GCC 4.3.4, Python 2.6.5 and Boost 1.41.0 32bit and 64bit Debians/Ubuntu. The problem does not seem to happen on Windows XP. I have embedded the Python interpreter in the attached http://old.nabble.com/file/p29579563/run_python.cpp run_python.cpp . When running this with the attached script http://old.nabble.com/file/p29579563/test.py test.py and which uses a test module http://old.nabble.com/file/p29579563/test_date_time.cpp test_date_time.cpp , the following Boost.DateTime error occurs: $ run_python test.py out() - entry out() - to_simple_string(): 2010-Aug-31 14:30:33.439172000 out() - manual format: 2010-Aug-31 14509:17:19.172000 out() - oss.str(): 2010-Aug-31 14509:17:19.172000 out() - now: Traceback (most recent call last): File "test.py", line 6, in <module> test_date_time.output() IndexError: Year is out of valid range: 1400..10000 However, when running the same script via python it is fine: $ python test.py out() - entry out() - to_simple_string(): 2010-Aug-31 14:30:31.208160000 out() - manual format: 2010-Aug-31 14:30:31.208160000 out() - oss.str(): 2010-Aug-31 14:30:31.208160000 out() - now: 2010-Aug-31 14:30:31.208160000 out() - exit Note that the time stamp in the first example is corrupt. Note also that the valid range error does not occur when using the date and time facets manually but when streaming the ptime object to std::cerr. The problem first arose for me when using Boost.Log with separate Python modules via *both* run_python and /usr/bin/python. See http://sourceforge.net/projects/boost-log/forums/forum/710022/topic/3748054 http://sourceforge.net/projects/boost-log/forums/forum/710022/topic/3748054 For this simple case, /usr/bin/python seems okay but the run_python error is identical to what happens in our proper application (where Boost.Log is used and multiple Python modules loaded). Has anyone witnessed similar behaviour? Or can they please test my example out? Thanks for any help, Sam -- View this message in context: http://old.nabble.com/-Boost.DateTime--Boost.Python--Year-out-of-valid-range... Sent from the Boost - Users mailing list archive at Nabble.com.