Chrome has a built-in anti-virus that scans files that you download. Sometimes, when you’re downloading a seemingly harmless file, Chrome will block it saying the file is not commonly downloaded and may be dangerous. This mostly happens with scripts, executables, and zipped files. Here’s how you can fix it.
When you choose to ignore Chrome’s warning, you run the risk of downloading a malicious file. The file won’t run automatically once it is downloaded but remember that it could be malicious.
Fix ‘file is not commonly downloaded and may be dangerous’
The file is blocked once it’s downloaded and you see a ‘Discard’ button next to it on the Downloads bar. Click the dropdown arrow next to it and select the ‘Keep’ option. This will save the file to your local disk.
The next thing to do is to scan it. Chrome often reports false-positives so you can either use a desktop anti-virus or you can scan the app with VirusTotal.
If VirusTotal or your desktop anti-virus also flags the file as dangerous, it is a very bad idea to still run it. If you used VirusTotal, you will have to manually delete the file yourself. If you scanned it with a desktop antivirus app, it likely deleted it for you or quarantined it. If the file has been quarantined, you should remove it from your system.
If you still suspect the file is getting a false positive i.e., it is being flagged as malicious when it shouldn’t be, you can do one of two things. First, check that you’re downloading the app from the right place. For example, if you’re trying to download VLC player and it gets flagged, make sure you are getting it from the official VLC player website and not from an online repository.
The second thing you can do is you can get in touch with the developer and let them know their app is being flagged. This of course won’t do much immediately. You will have to wait for the developer to respond and it is possible they choose not to do anything about it. In that case, you will need to find a different app that does the same job. It’s not easy but it is better than infecting your system.
If you’re thinking of risking the file even though Chrome, VirusTotal, and a desktop anti-virus app have all flagged it, try to run it in a sandbox to minimize the damage it will do.