Arm Mbed OS support forum

Error: Fatal error: L6002U: Could not open file ../../build/

Hi,
i got a strange error when i tried to compile my code:
Error: Fatal error: L6002U: Could not open file …/…/build/Thermo : No such file or directory
The file Thermo.c is placed in the root and i was able to compile it once. After trying to excange the file i got this strange error. Even when i comment out the usage of the file or cloning the project did not solve the problem.
How can i access the \build\ directory ?