System Workbench for STM32

Hi Tarek,
thank you for fast reply. After printing line:

Info : STM32L flash size is 16kb, base address is 0x8000000

there is a long delay (maybe 1 min?) and after that only two lines appear in console:

Error: failed erasing sectors 0 to 0
Error: flash_erase returned -5

and "Terminate faliled" as well as:

Error in final launch sequence
Failed to execute MI command:
load /media/DATA/ARMworkspace/temp_test/Debug/temp_test.elf

Error message from debugger back end:
Error erasing flash with vFlashErase packet
Error erasing flash with vFlashErase packet

alerts are open.

I've checked BOOT0 pin - it's ok (0V).
Also I've already installed newest CubeIDE - no change.

Regards,
Przemek