Date “1899/12/30” in Output File After Changing Data Type From “String” to “Date” in Tableau Prep with non-English OS

Published: 06 Jan 2023
Last Modified Date: 06 Jan 2023


The output file shows 1899/12/30 only upon changing from String to Date and when connecting to a published data source on Tableau Server.

Note: the Tableau Server OS is Non-English(e.g. Japanese, Korean, Chinese).  There is no issue when using Tableau Server with English OS.

For example, the preview data in Tableau Prep is correct.
User-added image

However, after outputting the data, all the dates are shown as 1899/12/30.


  • Tableau Prep Builder
  • Tableau Server Data Source
  • Windows CJK OS
  • Hyper


Please consider the below workarounds:

Option 1:

Duplicate the String field and change the Data Type from String to Date of the duplicated field then use it.
For example, duplicate [YMD] to [YMD-Copy] and change the data type for [YMD-Copy]. 

Option 2:

Change the field name of the String field at the Cleaning step. 
For example, from [YMD] to [YMD-1]

Option 3:

Do not change the Data Type and output the field as a String in Tableau Prep.
 Import the data to Tableau Desktop and change the data type.


This issue is currently being investigated under Known Issue ID 1465501. 
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