# Important information about using 12 digit BeadChip barcodes in GenomeStudio sample sheets

Illumina recently began using 12-digit BeadChip barcodes, which Excel automatically converts to scientific notation. If the BeadChip barcode column in the sample sheet is not reformatted as “Number,” the barcodes are not saved to the CSV file correctly. GenomeStudio does not recognize the barcodes when the sample sheet is imported, and the error message ‘The project can not be created. No valid samples were loaded.’ appears.

**Example**: After ‘123456789012’ is entered in the BeadChip barcode column, and the CSV file is saved, the barcode number is reformatted. In Excel, by default, the number is rounded to the nearest 6 significant digits, 123456000000, and is displayed in scientific notation as 1.23E+11.

To retain the full barcodes in the sample sheet, reformat the BeadChip barcode column as “Number” with 0 decimal places **before** the file is saved. To format the column correctly, do the following:1. Highlight column.\
2\. Right-click column.\
3\. Select **Format Cells**.\
4\. Select the **Number** tab.\
5\. Select **Number** and enter **0** as the number of decimal places.\
6\. Save the file as .csv and use to create GenomeStudio project.

If the sample sheet is reopened in Excel, the format of the BeadChip barcode column is not retained. The sample sheet opens with the column reverted to scientific notation. If changes are made to the sample sheet, requiring it to be saved, the BeadChip barcode column must be reformatted as “Number” with 0 decimal places before saving.

The sample sheet can be checked for accuracy using a text editor, such as Notepad. The sample sheet can also be edited in Notepad without any formatting issues.

For a demonstration of how to properly format a sample sheet, refer to the Support Short video, [How to Format Sample Sheet for Genomestudio Genotyping](https://www.youtube.com/watch?v=gs0HO1OI60k).

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #1422), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000001422%20-%20Microarray%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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