I'm trying to import a spreadsheet with dates and export it again. But the cell reads ### in the exported file. It's shown in the screenshots. This is my code.

file = Import["import.xlsx"];
Export["export.xlsx", file];

Is there some way to get this working? I'd like the export file being the same as the import file.

I was trying this with Mathematica 12 on Linux and Mathematica 11 on Windows.

Here's the import file.


Thanks a lot!

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  • 1
    $\begingroup$ probably has to do with the dateformat that is set up in Excel/Libreoffice. As you can see in the cell content, the date is correctly exported from Wolfram. $\endgroup$
    – FredrikD
    Commented Nov 19, 2019 at 7:35

1 Answer 1


Assuming that the file is a list of dates and that the issue isn't a formatting of the cell in Libreoffice then you could do this:

file = Import[NotebookDirectory[] <> "importdate.xlsx"]; 
fileII = DateString[#, "ISODate"] & /@ Flatten[file]; 
Export[NotebookDirectory[] <> "export.xlsx", fileII]

DateString will format the date as an ISO date

  • $\begingroup$ Thanks, that works! I still wonder if it's possible to export the DateObject as such in the excel format but that's more curiosity. (By the way, I tried with both, LibreOffice and MS Office - it's the same) $\endgroup$
    – tukan
    Commented Nov 19, 2019 at 17:15
  • 1
    $\begingroup$ Note that ISODate was introduced in Mathematica version 12. $\endgroup$ Commented Mar 14, 2023 at 17:20

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