Emailed Excel workbook appears broken after being attached

Question

I have worked a bit with an email attachment issue, and can now send attachments through email, through a script.

When the email comes in, I double-click the attachment, and Excel 2016 opens, with a dialog reading: We found a problem with some content in 'attachment.xlsx'. Do you want use to try to recover as much as we can? If you trust the source of this workbook, click Yes. I click Yes, it works. If I open the original file from the same server through Samba, it works fine. Only after it's gone through email does it appear to not be perfect.

What can I do to get rid of this dialog, so the recipient does not see it constantly? I plan on running the script weekly, with a new Excel file each week.

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The command that runs: (uuencode /path/to/file.xlsx file.xlsx; echo $BODY) | mail -r [e-mail] -s "Subject Line" [e-mail]

The file size is increased by 1 byte after being emailed. In this case, it's now 18738 bytes after being emailed. The SHA256 hashes are different between the two files.

Answer 1

uuencode definitely changes the file. You would need to uudecode on the other end to get the original file back.

To prove this to yourself run this:

uuencode /path/to/file.xlsx file.xlsx > testfile.xlsx

Do you get a valid Excel file?

Now:

uudecode /path/to/testfile.xlsx testfile.xlsx > testfile2.xlsx

Is testfile2.xlsx a valid Excel file?

SOLUTION: You can either decode the file on the other end or use a modern mail attachment function: You can add the heirloom-mailx package to Debian to add the -a attachment feature.