If you want to preview the data in a .CSV file before you import the file to vSphere, VMware recommends that you make a copy of the .csv file. Do not open the original file in Microsoft Excel as this might change the data formats of certain cells, which might cause issues in future releases.
If you attempt to import a .csv file that you first open in another program, the Import License Keys Data wizard displays a warning that the file you use is not in the correct format, and that some of the data might not be available in vSphere.
Even if you successfully import the .csv file after you reformat it, the reformatting might corrupt the data, which might cause the last page of the wizard recommend some invalid actions.
Incorrect Use of a CSV File
You export the correct report in My VMware and generate the correct .csv file, but, in order to view the information more clearly, you open the .csv file in Microsoft Excel and reformat dates and numbers, such as the contract start and end date, the order date, the order quantity. For instance, you change the formatting of the date from 11.10.2015 to 10/11/15, which might cause the UI to display missing data for some of the columns of the .csv file.