Мы не можем понять что у вас за проблема, опишите более понятнее и детальнее.

Hello, before downloading a video, hold down the <Alt> button and then the download button.

Hello, please, send us more details regarding the problem.

Hello, in order to help you better I need the following information.
Please, send me the information listed here: http://en.savefrom.net/user.php?info=1

Hello, please, send us more details regarding the problem.

Hello, before downloading a video, hold down the <Alt> button and then the download button.

Hello, most likely you have Safari.

Before downloading a video, hold down the <Alt> button and then the download button.

Hello, what kind of notification?
Describe in more detail.

Hello, please, send us more details regarding the problem.

Hello, please, send us more details regarding the problem.

For the better understanding it'll be great to see a screenshot with the error. 

What is your Operating System?

What’s your country?

How is the name of your browser?