My web application passes this file to POI after uploading it. That works. When I try to write it back out, the sky falls.
dump-update-tracking-20151205.xlsx (application/vnd.openxmlformats-officedocument.spreadsheetml.sheet), 12.46 KB, created by wataylor on 2015-12-06 02:21:51 UTC
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Creator: wataylor
Created: 2015-12-06 02:21:51 UTC
Size: 12.46 KB

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Attachments on bug 58694: 33327