Why can't I open files downloaded from attachments, i.e. from an email?

[AC Question]

i cant open files downloaded from attachments ie from an email

When I have received an email with an attachment in i cann download it OK but when I try to open it a box appears saying Can't Open File ?????

 

[Crashdamage]

Re: i cant open files downloaded from attachments ie from an email

You very likely don't have an app installed that can handle that particular type of file.

I need the file extension of the attachments. The extension is the letters after the dot at the end of the file. For example, a filename might be xxxx.doc or xxxx.exe. The letters after the dot determine what software will open a file. So what is the extension of the attachments?

Android since v1.0. Linux user since 2001.