ARCHIVED: In Microsoft Excel, why are the dates in my Mac spreadsheet malformed when I open it in Windows?

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Microsoft Excel uses the time and date convention for the system in which you open the spreadsheet. In Windows, Absolute System Time starts in 1900; on Macs, time begins in 1904. Both versions of Excel are capable of using either 1900 or 1904 as a starting date. To change the starting date setting, follow the appropriate instructions below.

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Excel 2011 and 2008 for Mac OS X

  1. From the Excel menu, select Preferences....
  2. In the Preferences window, click the Calculation icon. To use the 1900 absolute time, make sure Use the 1904 date system is not checked.
  3. Click OK.

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Excel 2010 for Windows

  1. From the File menu, select Options.
  2. In the column on the left, click Advanced, and scroll down to the section labeled "When calculating this workbook:". Check Use 1904 date system.

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Excel 2007 for Windows

  1. From the Office Button menu, select Excel Options.
  2. In the column on the left, click Advanced, and scroll down to the section labeled "When calculating this workbook:". Check Use 1904 date system.

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Last modified on 2018-01-18 08:42:46.