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can't run draw test harness and samples anymore

Peter's picture


two months ago I downloded OCCT 6.5.3 and tried to execute the samples and draw test harness. Everything worked fine. But now, I get this error message when I try to execute programs: the procedure entry point "??task_group_context@tbb@@QAE@XZ" couldn't be located in the dynamic link library "tbb.dll".
I reinstalled OCCT but didn't help. My OS is Windows 7 Professional 64-bit. Is it possible that an Windows Update is the reason for the troubles?
Please let me know how I can solve this problem.
Thank you in advance.

Kind regards


Forum supervisor's picture

Dear Peter,
First you should decide: do you really need TBB?
In OCCT6.5.3 only Standard and BRepMesh units may use TBB services.
If your answer is 'yes', you may check tbb.dll with dependency walker to identify the real reason.
if - 'no', you may rebuild OCCT6.5.3 without TBB. Just comment line "set HAVE_TBB=true" in 'custom.bat' file.

Roman Lygin's picture


Probably your environment got contaminated with some software you recently installed, which brings tbb in itself. Now when you try to start OCC another tbb version gets loaded instead of one shipped with OCC. As TBB provides binary compatibility, chances are that an older version has been installed.

To check which tbb is used you might want to inspect the PATH variable and to use Dependency Walker. You will probably need to make sure that OCC's tbb appears in the PATH prior to the other one - using .bat files should help.

Good luck,