What Is CSV File Garbling? Causes and How to Fix It in Excel

Contents

What Is CSV File Garbling? Causes and How to Fix It in Excel

When you open a CSV file in Excel and see strange characters like “ã‚¢ã‚¤ã‚¦ã‚¨ãƒ¼ãƒ«” instead of readable text, it can be confusing and frustrating. This issue, commonly known as “character garbling” or “mojibake”, occurs when the file’s text encoding doesn’t match Excel’s reading settings.
In this article, you’ll learn why CSV files become garbled, how to fix them, and how to prevent encoding issues in the future—all using Excel’s standard features.

✅ Understanding CSV File Garbling in Excel

CSV (Comma-Separated Values) files are text-based data files where values are separated by commas. When Excel opens a CSV file, it automatically interprets the text using a specific character encoding, such as UTF-8 or Shift-JIS (SJIS).
If the encoding doesn’t match the file’s actual encoding, Excel displays unreadable characters instead of text.

・What Is Character Encoding?

Character encoding defines how characters (letters, numbers, symbols) are represented in binary. For example:

UTF-8 is common in web environments and supports multiple languages.
Shift-JIS is mainly used for Japanese environments on Windows.

When a CSV file created in UTF-8 is opened in Excel, which expects Shift-JIS, the mismatch causes garbled text.

・Common Symptoms

You might notice:

Names or addresses turning into unreadable strings (e.g., “ãƒ†ã‚¹ãƒˆ” instead of “テスト”).
Only specific cells are corrupted while others display normally.
Excel preview in File Explorer shows garbled data even before opening.

✅ Main Causes of CSV Garbling

Understanding the source of encoding issues helps prevent them.

・Different Software Environments

If the CSV was exported from:

A web system (often UTF-8)
A Mac or Linux environment
A foreign online tool (e.g., Google Sheets, Shopify)
…Excel on Windows may not interpret it correctly because it defaults to Shift-JIS.

・Missing Encoding Declaration

CSV files are plain text without metadata. Unlike Excel’s .xlsx, they don’t store encoding info. Therefore, Excel must “guess” the encoding, and that guess is often wrong.

・Copy-Pasting Between Systems

If data was copied from a UTF-8 environment and saved with Excel’s “Save As CSV,” the mix of encodings can corrupt specific characters such as Japanese kana or symbols like “￥” or “—”.

✅ How to Fix Garbled CSV Files in Excel

There are several reliable ways to open CSV files correctly, depending on your version of Excel.

・Method 1: Use the Data Import Feature

This is the most effective and safest way to control encoding.

Open a blank Excel workbook.
Go to the Data tab → Click From Text/CSV.
Select your CSV file.
When the preview appears, look for the File Origin or Encoding dropdown.
Choose the correct encoding (for Japanese CSVs, try “65001: Unicode (UTF-8)” or “932: Japanese Shift-JIS”).
Confirm the preview displays text correctly.
Click Load to import the data into Excel.

💡 Tip: Once loaded, you can save the workbook as .xlsx to preserve encoding consistency.

・Method 2: Use the Legacy Text Import Wizard

Older Excel versions (before 2019) or Office 365 users who enable the legacy wizard can import with more control.

Open Excel and choose Data → Get External Data → From Text.
Select the CSV file.
Choose Delimited → click Next.
Set delimiter (usually comma).
Before finishing, specify File Origin as “UTF-8” or “Japanese (Shift-JIS).”
Confirm the preview, then load data.

To enable the legacy wizard in newer Excel versions:

Go to File → Options → Data → Show Legacy Data Import Wizards → From Text (Legacy).

・Method 3: Change Encoding Before Opening (Using Notepad)

If Excel doesn’t provide encoding options, you can manually re-save the file.

Right-click the CSV file → Open with Notepad.
Go to File → Save As.
Choose UTF-8 in the Encoding dropdown.
Save under a new name, e.g., “data_utf8.csv.”
Open the new file in Excel.

This method ensures Excel reads characters correctly, especially for mixed-language data.

✅ Preventing CSV Garbling When Exporting Data

If you regularly export data from systems to Excel, consider these preventative measures.

・Always Specify UTF-8 Encoding

When exporting CSV files from web apps, tools like Shopify, Google Sheets, or CRM systems often allow encoding selection.
Choose UTF-8 if possible—it’s widely supported and less prone to corruption.

・Avoid Opening CSV Files by Double-Clicking

Opening CSV files directly via double-click forces Excel to guess encoding.
Instead, always import from the Data tab or use the Text Import Wizard.

・Save Excel Files as XLSX Instead of CSV

If you edit and share data frequently, convert the CSV to .xlsx format immediately after import.
Excel’s native format preserves encoding and avoids corruption upon reopening.

・For Japanese Data, Prefer Shift-JIS When Sharing Internally

If your organization still relies on Shift-JIS systems (for example, accounting software), saving files in Shift-JIS ensures compatibility.
However, remember that UTF-8 is more flexible for modern web-based tools.

✅ Advanced: Checking File Encoding Before Opening

To ensure accuracy before opening, you can confirm a CSV file’s encoding.

・Using Windows Notepad

Open the file in Notepad.
Go to File → Save As.
Check the Encoding field—it shows the current type (UTF-8, ANSI, etc.).

・Using Excel Power Query (Optional)

If you use modern Excel, Power Query (part of the Data tab) automatically detects encoding and allows adjustments during import.
Although not required, it’s a powerful way to handle large CSV datasets safely.

✅ Common Pitfalls and How to Avoid Them

Even after fixing encoding once, new files may still become garbled. Here’s how to minimize risk.

・Editing CSV Files in Excel and Re-Saving

When you edit a UTF-8 CSV in Excel and save again, Excel may revert it to Shift-JIS.
To avoid this:

Re-import and export with UTF-8 encoding.
Or use Notepad to convert before saving.

・Sharing Files Between OS (Windows ↔ macOS)

Mac uses UTF-8 by default, while Windows often assumes Shift-JIS.
If collaborating across systems, standardize file encoding to UTF-8.

・Hidden Characters or Line Breaks

Sometimes, extra line breaks or invisible symbols can trigger garbling.
Open the file in Notepad++ or VS Code to check for unexpected symbols before importing.

✅ Practical Example: Fixing a Garbled Customer List

Imagine you exported a customer list from your e-commerce dashboard and saw unreadable characters in Excel.
Here’s how you’d fix it:

Open Excel → Data → From Text/CSV.
Select the file.
Change File Origin to UTF-8.
Preview shows customer names correctly.
Load data and save as “Customer_List.xlsx”.

Now your data is readable and reusable for reports, analysis, or mail merges.

✅ Summary: How to Fix and Prevent CSV Garbling in Excel

CSV garbling occurs when Excel’s assumed encoding differs from the file’s actual encoding.
Use Data → From Text/CSV to manually select the correct encoding (UTF-8 or Shift-JIS).
Re-save garbled files in UTF-8 via Notepad if Excel doesn’t import properly.
Avoid opening CSVs by double-clicking—always import manually.
Prefer .xlsx for everyday Excel work to maintain consistent encoding.

By understanding encoding principles and following these methods, you can handle CSV files smoothly and prevent future issues—saving time and ensuring clean, readable data in Excel.