How to reset Master Password?

Strangely the password i thought i set wasn’t the one and now I’m locked out of my passwords for my pc and mobile
Is there no way to reset the master password if forgotten?

Sorry, there isn’t. It’s designed this way so no one (including us in Avast) is able to unlock your vault and access your passwords / credit cards without knowing the master password.

so how can I recover the functionality of avast and pw of my pc ???
thank you

I assume by “functionality of avast” you mean that you have set up your Avast to be password protected? Like Settings → General → Password → Protect Avast with a Password option? If so, I can’t help you as I don’t deal with core Avast, only with Avast Passwords product (the password manager)