I'm putting old files to fresh Mac and on one external drive, there is bunch of video files I downloaded from Youtube and Tumblr at one point few months ago.

Would it be safe to put them to fresh Mac or could those files be harmful? There didn't seem to be anything bad with them before, but as this is fresh Mac I'm more careful now.

Should I keep them away from fresh Mac just in case?

  • "downloaded from YouTube"? You can't download anything from YouTube—you can however use an outside YouTube-to-MP3 converter, which could lace the downloaded files with any malware it wanted to. So it depends!
    – owlswipe
    Feb 27, 2017 at 2:32
  • @owlswipe Hello! I used this, before heard it is kind of illegal and stopped. addons.mozilla.org/en-us/firefox/addon/download-youtube Only danger for youtube and tumblr files to be infected would stem from downloader then? The video files in Youtube and Tumblr server can't be infected?
    – Tamirom
    Feb 27, 2017 at 10:11

1 Answer 1


Well there are two points to this.

A.) there is a question of whether or not the files themselves contain any malicious code, which is hypothetically possible, but not likely. Owlswipe's comment is not correct in saying you cannot download files from YouTube, you can do so both through YouTube Red, as well as downloader extensions (which by the way are not illegal).

All a YouTube downloader extension does is use a program (often times wget, or something similar) to make a copy of the video file that is referenced in the html for that video's page. While it is possible for a downloader extension to infect that video file, it is quite unlikely for it to happen in practice. As far as files from Tumblr go you can probably safely assume the majority of posters on Tumblr do not have the knowledge how, or a reason to inject malware into a picture they are posting. Also seeing as both of these sites use HTTPS (Secure HyperText Transfer Protocol) it would not be possible for someone else to slip malware into either the file as you were downloading it or the page when you were connecting. Though there is always technically the possibility that their severs could be hijacked, it is very unlikely that it happened during the specific time you were downloading files. Which brings me to the second point.

B.) Macs run macOS, which is built on Unix. Unix is very secure, and generally hard to infect with malware. While this does not mean you should stop caring about keeping your computer safe (because it is still possible for a Mac to get infected), as long as you don't enter your password into random prompts saying a program you didn't launch wants to modify your system you should be fine. Typically it is only Windows that is vulnerable to the type of attacks used by malware that is contained in an image or video file, and it is because of the way Windows handles both security access and multimedia with a connected system.

All in all your Mac should be fine if you move your older files to it. Unless you know for sure that someone had hijacked the YouTube or Tumblr servers on the day you downloaded the files, you don't realistically need to worry about it getting infected by them. With that said always be careful when running programs you download from the internet, even on a Mac, as it is easier for malware in a program to infect any system than it is for malware in a video or image file.

  • This isn't correct, in multiple ways! Downloaded YouTube videos can't be copied to your disk as files (MP4 or otherwise) as per macxdvd.com/youtube-download-video/…. And, Extensions used to download YouTube videos are illegal because they violate the YouTube terms of service, which state "You shall not download any Content unless you see a “download” or similar link displayed by YouTube on the Service for that Content.You shall not copy...or otherwise exploit any Content for any other purposes without the prior written consent of YouTube."
    – owlswipe
    Feb 27, 2017 at 15:24
  • And even hinting that a Mac is less vulnerable than a PC to malware is a bad idea. Exploits that get around GateKeeper (arstechnica.com/security/2015/09/…) show up nearly all the time and being on an out of date version of macOS could make you vulnerable to numerous of these. So watch out what you suggest here!
    – owlswipe
    Feb 27, 2017 at 15:26
  • -1 for the false information, though you do make a good point about HTTPS. Let me know if you edit your answer and I would consider changing to an upvote.
    – owlswipe
    Feb 27, 2017 at 15:27
  • @owlswipe A.) Violating a website's terms of service is not inherently illegal, in this case it simply means they have the right to revoke your access to their service, as YouTube (and by extension Google) do not hold the copyright to the content being downloaded, the uploader does, and Google does not hold the legal authority to enforce said copyright on behalf of the holder without the holder's explicit request and verifiable statement that Google is to act as their representative on the matter. They have a right to terminate your account/ block your IP address, it is not however illegal. Feb 27, 2017 at 19:04
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    @owlswipe Oh, I agree that they're certainly legally grey at best and outright sketchy at worst in almost every situation, I just wanted to make sure the verdict was left to a case-by-case basis for the sake of fairness, that's of course not to say most cases wouldn't still be considered at least some form of copyright infringement, I just like to account for outliers as well :3 Feb 27, 2017 at 23:54

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