Error exporting project from MBED to uV

Sorry guys, I am just starting out on this IDE when MBED struggled to run Ticker and Uart together :(

after the export, the build shows this error :
.\build\Nucleo_printf3.axf: error: L6002U: Could not open file mbed/TARGET_NUCLEO_F072RB/TOOLCHAIN_ARM_MICRO/stm32f0xx_hal_sp: No such file or directory

I checked the MBED and uV project folders, the file does not exist anywhere.

the project is attempting to use UART, Ticker, DAC

#include "mbed.h"

Ticker toggle_led_ticker;

Serial pc(SERIAL_TX, SERIAL_RX);  // 9600 bauds, 8-bit data, no parity
//Serial pc(PA_2, PA_3);          // MBED won't run true serial ports ?? regardless here, all
                                  //                   outputs through USB virtual comm ports
AnalogOut my_output(PA_4);
DigitalOut myled(LED1);

#define PI        (3.141592653589793238462)
#define AMPLITUDE (1.0)    // x * 3.3V
#define PHASE     (PI * 1) // 2*pi is one period
#define RANGE     (4096/2) // 12 bits DAC
#define OFFSET    (4096/2) // 12 bits DAC

// Configuration for sinewave output
#define BUFFER_SIZE (360)
uint16_t buffer[BUFFER_SIZE];

void calculate_sinewave(void);
void toggle_led(void);
void Ramp_DAC(void);
void Dac_Sine_wave(void);

int Dac_Output =0;
int Buffer_pointer =0;

int main() {

    calculate_sinewave();

////    toggle_led_ticker.attach(&toggle_led, 0.000006);      //this is also output on Pin PA5, DAC2  //5.75uSec update gives fastest sinewave = 173.913kHz
////    toggle_led_ticker.attach(&Ramp_DAC,   0.000006);
//   toggle_led_ticker.attach(&Dac_Sine_wave, 0.000006);// this stops the UART functioning in MBED


  int i = 1;
  pc.printf("Hello World !\n");
  while(1) {
      wait(0.1);
      pc.printf("Step %d\n", i++);
      myled = !myled;
  }
}



void toggle_led()
{
    myled = !myled;
}

void Ramp_DAC(void)
{
    Dac_Output = Dac_Output + 2000;
    //if(Dac_Output >4096) Dac_Output=0;
    if(Dac_Output >=3000) Dac_Output=0;
    my_output.write_u16(Dac_Output);
//    my_output2.write_u16(Dac_Output);
}

void Dac_Sine_wave(void)
{
    Buffer_pointer ++;
    if (Buffer_pointer >359) {
        Buffer_pointer =0;
        toggle_led();
    }

    my_output.write_u16(buffer[Buffer_pointer]);
    //my_output2.write_u16(buffer[Buffer_pointer]/2);
}


// Create the sinewave buffer
void calculate_sinewave(void)
{
    for (int i = 0; i < BUFFER_SIZE; i++) {
        double rads = (PI * i)/180.0; // Convert degree in radian
        buffer[i] = (uint16_t)(AMPLITUDE * (RANGE * (cos(rads + PHASE))) + OFFSET);
    }
}