Thanks again for your help and have a good weekend!

Hi lbernstone - Yep, spot on! Changing that option to "=n" definitely removed the error message. Thank you very much for your help, I would never have guessed that that was the cause.
Can you tell me please how you found the connection to CONFIG_MBEDTLS_X509_REMOVE_INFO as the cause?

I am getting the following error message when i use IDF 6.0 idf.py build to compile an Arduino sketch:

[1443/1456] Building CXX object esp-idf/arduino/CMakeFiles/__idf_arduino.dir/libraries/NetworkClientSecure/src/ssl_client.cpp.obj
:
:
C:/Users/Mike/Projects/components/arduino/libraries ...