I'm working on an attachment upload script for a professional / business website, which will display a list of all attachments with an icon representing their file type.

I have icons for most expected filetypes, word, pdf, excel etc...

But I need one for 'Unknown file type', just in case someone uploads a random file. Could anyone suggest an icon?

A quick google search produces mainly question marks, which I guess are fine but I'm wondering is there possibly a convention for this?

  • I think the convention would be to use a question mark. Apr 29, 2014 at 11:31
  • commonly used icon (question mark) could be treated as a convention in this case Apr 29, 2014 at 11:32
  • Note that this has just been cross-posted to GD so it may need to be migrated and merged. Apr 29, 2014 at 11:34
  • Deleted from GD
    – Daft
    Apr 29, 2014 at 11:42
  • Look at what the file browser of the OS does. Windows Explorer shows the standard "document" icon for a file with an extension that has not been registered. Other OS's file browsers probably do something similar. Apr 29, 2014 at 13:43

1 Answer 1


Well, it depends on if you want to show "unknown" or "generic". Unknown (question mark) can be seen as a file that has some unknown properties, while in most cases, what the system wants to show is "this is a file that I don't have an icon for". I would therefore suggest a generic file icon.

enter image description here

If there may be cases where files without file ending are uploaded I guess the question mark would be appropriate since the system doesn't know what file type it is. In the other cases - the system knows what file type it is.

  • Cheers Henrik, this is what I was looking for. Thanks for the informative answer too.
    – Daft
    Apr 29, 2014 at 11:42

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