Depending on which platform you use with Gmail, you can open a range of attachments without downloading them. However, you can't open some attachment types. These tend to be program-specific files ...

Here's how to open a RAR file with The Unarchiver app on a Mac computer. 1. Go to the App Store and download The Unarchiver. It's a free download. 2. The app will prompt you to open it after it ...