Whenever you recieve a file attachment in gmail from your friend/client, its automatically scanned before the download link is offered and you need to make sure that you also have a good antivirus program installed in your computer before you unzip and start using those files.

Gmail Antivirus Scanning system automatically scans the whole file and removes the virus and allows you to still access the file after its clean and makes sure that your PC is safe after downloading, and if the virus cannot be removed then it just wont allow you to download the file.

Sometimes the files are not scanned because of unknown reasons and gmail gives you a message like ‘Oops… the virus scanner has a problem right now’ which means that you can download at your own risk and later not blame gmail team for any virus which is passed into your pc. This is the same case when your own PC is infected and you are sending a email to someone with a attachment which is infected, gmail asks you to remove the attachment and send the file.

Here is a case when gmail could not scan the file attachment and you should not download this kind of file because it can harm your PC. Make sure you always scan files which are downloaded via email before actually using them.