Guide
CSV looks garbled in Excel—or everything lands in one column. Start here.
Those two symptoms look related, but they usually come from different things. Check encoding first for garbled text, delimiter first for one-column data.
First, the reassuring part: the file is often fine
You open a CSV and the Japanese text turns into nonsense. Download it again. Same result. It is tempting to assume the export is broken, but very often Excel is simply reading the text with the wrong character encoding.
A CSV is a plain text file wearing a spreadsheet-looking outfit. It does not always carry enough information for Excel to know exactly how it should be opened.
Garbled text and one big column are different problems
If the characters are unreadable, think encoding: UTF-8, Shift_JIS, and so on. If the text is readable but every field sits in column A, think delimiter: comma, tab, semicolon.
That distinction saves a lot of random trial and error.
Open from Excel instead of double-clicking
Use Excel’s data import flow, choose the file, then try the encoding and delimiter options while watching the preview. When the Japanese looks normal and the columns line up, load it.
Re-exporting the same file repeatedly will not help if Excel keeps guessing the same way.
A CSV can open correctly and still change your data
This is the sneakier problem. Excel may turn `00123` into `123`, or interpret something like `1-2` as a date. Nothing looks “broken,” so the change is easy to miss.
For product codes, IDs, SKUs, and long numbers, compare with the original before uploading the edited file anywhere.
A quick way to decide what to test first
Unreadable characters? Test encoding. Readable text but one giant column? Test the delimiter. Values changing after Excel opens the file? Compare data types and the original CSV.
You do not need to understand every CSV detail before you start. Match the symptom to the first likely cause, then verify with a preview.
Related tools and references
When you want the full model
If you want more than the immediate fix and would like one model for CSV structure, UTF-8/BOMs, quoting, and Excel conversions, read CSV Complete Guide.