answer from Frederic Devernay ( Redirecting to Google Groups)
If you launch natron from the command-line, you should see the messages there.
OFX::log() logs by default to a file names ofxTestLog.txt, which may be located next to natron.exe or in the plugins dir, I don’t remember. Look for that file.
I don’t have a windows machine, so I can’t help you more.
Natron is built with MSYS/MINGW, and I don’t know if the VS debugger can be attached to an MSYS/MINGW binary. Try google.
Anyway, this forum is not active anymore, and you should ask your questions on the new forum at https://discuss.pixls.us/c/software/natron
There is also a discussion on building Natron for windows there: Building Natron on Windows from scratch
Maybe Windows users will be able to help you