How to return the Arduino Pro Micro to working condition?

Question

Arduino

Good afternoon, dear radio amateurs!
Please tell me why the Arduino Pro Micro (Chinese without a button) after uploading the sketch is no longer defined as a com port? And how can this be avoided in the future?
I tried to assemble a CO meter according to the scheme from the article .
The components are all as in the article, the sketch was tested in the Arduino IDE and after uploading the board is no longer defined as a COM port.
The programmer in the settings was: AVRISP mkII
And there is no sensor reading on the screen, only the inscription: "Sensor CRC error".
I will be very glad to your advice!
Thank you!
PS I tried to do a reset, through a resistor of 1 and 10 kOhm (RST + GND), but to no avail.
I read that I could wipe the loader... but how? And how to return it? And most importantly, how not to do it again?

Answer 1

Try flashing the bootloader via ICSP using a programmer.