Unfortunately, when a data file in CSV or tab-delimited format is simply opened directly with Excel, it will strip out leading zeroes when present in account numbers, ZIP/post codes, and so forth. Fortunately, there is a data import tool present in Excel that will allow you to get around this issue:
- Open a new, blank spreadsheet in Excel.
- Go to the Data tab up top.
- Click From Text and choose your data file.
- If asked about format, for CSVs, be sure to choose Comma-Separated Values, or Comma-Separated Values (Windows/ANSI/DOS) or something along those lines if offered more than one choice for CSVs. For tab-delimited data files (these are usually the TXT extension instead of CSV), choose Tab-Delimited.
- Click each column containing numbers and choose the Text format.
- Excel will leave all the numbers alone, retaining all the leading zeroes in account numbers, ZIP codes, and so forth. The apostrophe or arrow icon it may show at the beginning of each number afterwards is simply indicating they're in text format, AKA "as is" and unformatted data.
- Save as an Excel file for any further manipulation necessary to prepare for importing. This can be your master file in case any changes are needed.
- When done, save a copy of the file as a CSV file for importing. Click yes on the "may lose formatting" warning prompt. No data will actually be lost after having followed the above steps.