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I recently had someone ( try to email me ( and including in their email 3 text files and a .docx file. The email never reached me and they never received any bounce message. I eliminated attachments one at a time and determined that one of the text files was causing the problem. Inspecting the text file, it appears to contain a number of non-ascii characters. I stripped out all printing ascii characters and newlines with the following command:

dcollins@laptop:~/Downloads$ tr -d "\012\015\040-\176" < filename.txt | od -x
0000000 e9e9 e9e9 e9e9 9595 9595 9595 9595 9595
0000020 9595 9595 9696 9797 9797 aeae aeae aeae
0000040 97ae 9797 9999 9999 9997

As you can see, the attachment contains several instances of 0xe9, 0x95, 0x96, 0x97 0xae, and 0x99. Shouldn't my mail program decide that this attachment contains non-ascii characters, base-64 encode it, and send it using MIME? I noticed that the other text attachments were transmitted as Content-Type: text/plain, but since I didn't receive the problem attachment, I can't tell what my client did with it. Is this a bug in my client or in my ISP's mail server?

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If someone else is trying to email you, then it is the sender's mail program, not yours, that has to MIME-encode the file. – grawity May 20 '12 at 9:20

Download a free email client, then resend your attachment with that client. If it still fails, it's your ISP. If it gets sent, it's your mail client.

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I've written a mail client or two, and it's feasible that there is a bug.

However, there's no evidence here that the text file itself isn't corrupt.

Have your colleague copy and paste the text into a new document and send that to you, to see if the problem recurs. Have him save the file both as ASCII and Unicode, and see if that's causing the problem.

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