Check downloaded files

Treat all files downloaded from the internet with caution, including files from sites, peer-to-peer networks, and messengers. Don't ignore antivirus and operating system warnings when you download files or run downloaded programs. If you're advised to disable your antivirus to solve a problem, you're dealing with suspicious content.

If you receive a file by email (even if it's "just a picture" and you know the sender), save the file to a disk. Before opening it, check it using an antivirus or online scanners.

Potentially dangerous:

  • Executable files with the .exe, .com, .bat, .cmd, .js, .vbs, .pif, .swf, .jar, .reg, .msi, .gg, .gadget, .htm, .html, .xhtml, .mht, and .chm extensions.

  • MS Office files (DOC, XLS, PPT, and other formats) and PDF documents that can contain macro viruses.

Almost every file has an extension: it indicates the file type. For example, postcard.jpg is an image: this is indicated by the .jpg extension. Sometimes, a pseudo-extension is added to the virus file name: for example, postcard.jpg.exe. Windows normally hides the real extension, so the file name is displayed as postcard.jpg. A user can easily mistake this file for an image and open it.

To avoid making such mistakes, enable the display of file extensions:

Windows 10
  1. Start → Explorer.
  2. Go to the View tab. Click Parameters.
  3. Go to the View tab and disable the Hide extensions for known file types option in the Advanced settings list.
  4. Click OK.

Windows 8.1
  1. Start → PS Settings → Control Panel → Appearance and Personalization → Folder Options.
  2. Go to the View tab and disable the Hide extensions for known file types option in the Advanced settings list.
  3. Click OK.

Windows 7
  1. Start → Control Panel → Appearance and Personalization → Folder Options.
  2. Go to the View tab and disable the Hide extensions for known file types option in the Advanced settings list.
  3. Click OK.
Windows 10
  1. Start → Explorer.
  2. Go to the View tab. Click Parameters.
  3. Go to the View tab and disable the Hide extensions for known file types option in the Advanced settings list.
  4. Click OK.

Windows 8.1
  1. Start → PS Settings → Control Panel → Appearance and Personalization → Folder Options.
  2. Go to the View tab and disable the Hide extensions for known file types option in the Advanced settings list.
  3. Click OK.

Windows 7
  1. Start → Control Panel → Appearance and Personalization → Folder Options.
  2. Go to the View tab and disable the Hide extensions for known file types option in the Advanced settings list.
  3. Click OK.