Avast is an Antivirus software that protects your device from online and offline threats. The Avast Activation Code Error 305 is a run time error that occurs if you had mistyped the activation code or if the license file is corrupted. If you wish to fix this error, follow the below-mentioned steps.
Solution 1: Retry the activation or retrieve your subscription
If you have purchased the activation key, you will receive the confirmation through email.
You can verify whether you have entered the correct activation code from the email you have received.
To retrieve your subscription, log in to your Avast Account.
Click the Copy to clipboard link next to the activation code for your subscription.
Now, the activation is copied to your clipboard.
To retry the activation process on your Windows computer, give a right-click on the Avast icon at the system tray.
Select the Subscription Information option from the pop-up menu.
In the Subscription Information window, select the Enter a valid activation code option and enter the correct activation code.
If you have purchased a license file, download a copy of it on your computer and activate the antivirus software to check if the Avast Activation Error 305 has been resolved.
Solution 2: Reinstall Avast Antivirus
On your Windows computer, open the Control Panel app.
Click on the Uninstall a program link underneath Programs.
On the Uninstall a program screen, select the Avast Antivirus software and click the Uninstall button.
If prompted, confirm your action by clicking the Uninstall button again.
This will remove your antivirus from your computer.