# Retention time locking error

Hi!

The acquire RTLock Calibration Data is done with a mixture standard. However, after choosing one peak that I need to lock the retention time, it appears a message "peak number must be >0 and < number of peaks". How could I fix the error and then it can go to the next step.

Thank you.

## Top Replies

• Hi , when you integrate the peak, try to make sure the baseline (red color line) is below the peak. Try to integrate other peaks, do you still get the same error?