METHOD: Schedule a Boot-Time Scan

• First open the Avast, from the left side click on the protection tab » ‘Scans‘ in the left menu. From the scan, overview click on ‘Boot-Time Scan‘ option.

• Once you reach on the Boot-Time Scan overview click on 'Install specialized definitions', it will add special virus definitions capable of detecting malware on inaccessible places for Windows. Once done click on the green button 'RUN ON NEXT PC REBOOT' and you are set.
• After then the message will appear 'Scan will run on next boot'. To cancel boot-time scan simply click on the ‘Cancel scheduled scan‘ link.

Source: How to Run Boot-Time (Startup) Scan in Avast Antivirus 2019

Hello.