Hi @projectX_V ,
It seems that this problem is relative to Arm Compiler 6.15. A toolchain version changed in Mbed Studio 1.4.0. Mbed Studio 1.3.1 was shipped with Arm Compiler 6.14. I’ll reach out to Arm Compiler team and ask about this problem. In the meantime the only thing I can recommend is switching to GCC_ARM: Switching to GCC - Installing | Mbed Studio Documentation
Thanks,
Arek - Studio team