CSV Repair Guides
Excel damages CSV files in a handful of predictable ways, and each one has a specific cause and a specific fix. These guides explain exactly what went wrong — with real values you will recognize from your own files — and cover both the repair and the import technique that prevents a repeat. Where a fix can be automated, the matching guide points you to the free browser tool that does it in one click.
All guides, by what went wrong
Numbers and codes Excel rewrote
Barcodes, ZIPs, SKUs, phone numbers and IDs — the damage that changes the data itself.
Excel Converts Numbers to Scientific Notation
Any number with 12 or more digits — UPC barcodes, EANs, container and account IDs — gets displayed as 8.85909E+11, and saving the file writes that notation over your real data. Learn why Excel does this, which digits are still recoverable, and the Data → From Text/CSV settings that stop it for good.
CSV Leading Zeros Disappear
ZIP code 00501 turns into 501, product code 0071589 loses its zero, and the upload validator downstream rejects your file. See why Excel treats these codes as plain numbers and three reliable ways to keep the zeros — importing the column as Text, the legacy Text Import Wizard, and automatic padding.
Long Number’s Last Digits Became Zeros
A 16+ digit card, IMEI or account number ending in zeros that shouldn’t be there? Past 15 digits Excel permanently rounds the tail — why it’s unrecoverable from the file, and the only real fix.
16-digit numbers guide →Add Leading Zeros That Actually Stick
Need to pad ZIP or product codes to a fixed width? Why a custom format vanishes when you save the CSV, and how to bake real leading zeros into the file so they survive a reopen.
Zero-padding guide →Google Sheets Drops Leading Zeros
Sheets strips 00501 down to 501 and turns long codes into 1.2E+11 on import, for the same reason Excel does. Learn the one File → Import checkbox that keeps every value as text — and what’s recoverable after the fact.
Excel Breaks Phone Numbers in CSV
The + stripped, the mobile 0 dropped, the number shown as 4.47E+11? Phone columns hit three of Excel’s traps at once. See which parts are recoverable after a save and how to import them intact.
Stored as Text” (Green Triangle)
That green triangle after a CSV import is usually a sign you did the right thing. When to convert a column to a real number — and, crucially, which codes you must leave as text so you don’t re-break them.
Green-triangle guide →Excel Dropped My Trailing Zeros (1.50 → 1.5)
Is 1.50 becoming 1.5 actually a problem? When it’s harmless (it’s the same number) and when it isn’t — prices, versions, codes — plus how to keep the literal zeros in the file.
Trailing zeros guide →European Number Format (1.234,56)
A file with comma decimals and dot thousands misread by a US/UK Excel? Why the decimal-mark locale mismatch mangles values, and how to convert them without corrupting your data.
European numbers guide →Characters and encoding
é, ???, boxes, Chinese-looking text and the BOM — everything that goes wrong between one program’s idea of a byte and another’s.
é Instead of é — Fixing Mojibake
When café becomes café, your file was written in UTF-8 but read as Windows-1252, so every accented character split into two wrong ones. Learn to spot the classic Ã, †and  patterns and reverse the damage — even in double-encoded files.
CSV Shows ??? or □ Instead of Letters
Unlike reversible é mojibake, literal question marks usually mean the letters are already gone. Learn to tell a permanent ? from a fixable replacement character or a harmless empty box — and rescue what you can.
UTF-8, BOM and Excel
Three invisible bytes — EF BB BF — at the start of a file tell Excel it contains UTF-8; without them accented characters break, yet with them some other tools choke. Learn what a byte order mark actually is, when to add one, when to strip one, and how to do either.
Save an Excel File as CSV UTF-8
Keep accents and symbols alive on export — the exact steps on Windows, Mac and old Excel, plus the BOM gotcha that trips up importers and how to work around a missing “CSV UTF-8” option.
CSV UTF-8 export guide →Change a CSV’s Encoding to UTF-8
An importer rejected your file as “not UTF-8”? Convert it in Notepad++, VS Code or Notepad — with the BOM-vs-no-BOM choice that decides whether the import finally works, and how to verify it.
Encoding conversion guide →ANSI vs UTF-8 for CSV Files
Excel’s Save As offers “CSV” and “CSV UTF-8” — which should you pick? What each really stores, when ANSI silently destroys accents and symbols, and why UTF-8 is the safe default.
ANSI vs UTF-8 guide →TRIM Won’t Remove the Space? (CHAR 160)
Cells look trimmed but VLOOKUP and de-dupe still fail? The invisible culprit is a non-breaking space (CHAR 160) that Excel’s TRIM ignores. How to detect it and clear it in one click.
CHAR 160 guide →Structure: columns, rows and delimiters
When the file parses into the wrong shape — one column, split rows, or a delimiter nobody expected.
CSV Opens in One Column
All forty fields crammed into column A almost always means a delimiter mismatch: your regional settings expect semicolons but the file uses commas, or vice versa. Fix it in under a minute with Text to Columns or a locale-aware Data → From Text/CSV import.
One-column CSV guide →Commas in Your Data Break the Columns
One comma inside an address split the row and shifted every column after it. The RFC 4180 quoting rule that fixes it, why some exporters get it wrong, and the honest limits of repairing a file that’s already misaligned.
Comma-in-data guide →Line Breaks Inside a Cell Splitting Rows
A multi-line address or notes field turned one record into several rows? The RFC 4180 rule that keeps a newline inside a cell, and how to fix a file that already split — distinct from the comma case.
In-cell line breaks guide →Excel Saves CSV With Semicolons
Excel exports semicolons and the next system wants commas? Why your regional list separator causes it, and the safe way to force comma output without breaking your formulas.
Semicolon-CSV guide →CSV Line Endings: CRLF vs LF
Seeing ^M, a blank row between every record, or the whole file on one line? That’s a CRLF-vs-LF mismatch. What each symptom means and how to normalize line endings for good.
TSV to CSV (and Back)
What a tab-separated file is, how it differs from CSV, and how to convert between them without breaking quotes or identifier codes — and where to find the free in-browser converter that does it.
TSV conversion guide →Dates Excel reinterpreted
The damage that looks like a formatting preference and is really a different day.
Excel Turns Values into Dates
Part number MAR1 becomes 1-Mar, the fraction 1-2 becomes 2-Jan, and the original text is gone the moment you press Enter — a problem so severe that geneticists renamed human genes to escape it. Learn every value pattern at risk and how to import them as text.
Excel Flipped My Dates DD/MM ⇆ MM/DD
A UK date like 04/11/2023 read as 11 April, and only the days of 12 or less silently flipped? That’s a locale mismatch. See the tell-tale mixed-alignment mess, the import fix, and why ISO YYYY-MM-DD ends it for good.
Working with CSVs without breaking them
Opening, merging, de-duplicating and choosing between CSV and a real spreadsheet.
Open a CSV in Excel Without Breaking It
Double-clicking is what wrecks your codes, dates and accents. The one safe import method — Data → From Text/CSV with columns set to Text — plus a table routing every kind of damage to its fix.
Safe-open guide →CSV vs Excel (.xlsx)
Why does saving as CSV drop your formatting, formulas and leading zeros? A plain-English comparison of the two formats, a decision table, and how to move between them without losing anything you can’t get back.
CSV vs XLSX guide →Remove Duplicate Rows From a CSV
Three ways to strip duplicate rows — a private browser cleaner, Excel’s Remove Duplicates, and Google Sheets Data cleanup — plus what actually counts as a duplicate and why the first row is the one that’s kept.
Duplicate-rows guide →Merge Multiple CSV Files Into One
Combine monthly exports into one file without copy-pasting in Excel. Four methods compared — a browser merger, Power Query From Folder, and the copy/cat commands — and which keeps your data clean.
Garbled Characters in a Shopify CSV
Product or order CSV showing Gaussé or strange symbols? Shopify needs UTF-8 — why Excel breaks it mid-workflow, and how to keep accents intact through import and export.
When a platform rejects your CSV
The damage above is what Excel did to the file. These guides start from the other end — the error message the platform gave you when the upload failed — and work backwards to the cell that caused it.
Shopify CSV Import Errors Decoded
“Invalid CSV header”, a variant that “already exists”, the file-size ceiling, and barcodes that arrive as 8.85909E+11. Every Shopify product-import failure, matched to the cell that caused it.
Amazon Flat File Upload Errors
Why a valid UPC is rejected as invalid, what happens to a 12-digit code once Excel has seen it, and the encoding setting that quietly breaks accented product titles in a flat file.
Amazon flat file guide →eBay Rejected Your CSV Upload
eBay answered “We couldn’t identify your template”, or your UPCs read 8.85E+11? How Excel rewrites Seller Hub and File Exchange files — template lines, barcode digits, encoding — and the browser repair for each.
Etsy CSV Special Characters and Lost Zeros
Etsy’s CSVs are download-only, so nothing fails loudly — titles turn into José-style garbage, SKUs and ZIP codes lose their zeros, and the file lands in one column. Repaired before the data goes back to your shop tools.
BigCommerce CSV Import Errors
“Invalid product SKU”, duplicate errors that outlive deleted products, and UPCs arriving as 8.98E+11 — what Excel did to the file, and the repairs to run before you upload it again.
Google Merchant Center Feed Errors
A gtin column full of 8.7986E+11, UPCs a digit short, and “Invalid UTF-8 encoding” across the feed. What Merchant Center’s GTIN and encoding errors mean — and which spreadsheet habit caused each one.
QuickBooks Won’t Import Your Bank CSV
The 3-column and 4-column layouts QuickBooks actually accepts, the date formats it rejects, and why an amount column with currency symbols or a stray blank row stops the whole import.
QuickBooks import guide →Mailchimp Rejected Your Contact CSV
Phone numbers turned into scientific notation, names arriving as José, semicolon-separated exports read as one column, and duplicate addresses — fixed before you re-upload.
Salesforce Data Loader CSV Errors
“Invalid CSV format” and the UTF-8 problems behind it: unescaped quotes, line breaks inside cells, the encoding Data Loader expects, and IDs that lost their leading zeros.
Salesforce Data Loader guide →CSV Too Big for Excel?
Excel stops at 1,048,576 rows and silently truncates the rest. How to tell whether you lost data, and how to split a large file into importable parts without opening it in Excel at all.
Oversized CSV guide →WooCommerce CSV Import Not Working
The product importer maps your columns to nothing, prices arrive as text, or accented product names break. The header names WooCommerce expects, and the encoding it needs them in.
WooCommerce import guide → Contacts Imported as José
Outlook and Google Contacts both export CSVs that the other reads with the wrong encoding, so every accented name arrives mangled. Fix the file once instead of editing 400 contacts by hand.
Garbled contacts guide →VLOOKUP Returns #N/A After an Import
The two values look identical on screen but never match: one is text and one is a number, or one carries a trailing space or a non-breaking space. How to find which, and fix the column rather than the formula.
VLOOKUP #N/A guide →CSV Shows Chinese Characters or Squares
A UTF-16 file read as 8-bit text renders as CJK glyphs or empty boxes — the data underneath is intact. How to confirm it, and convert the file to UTF-8 without losing a character.
Chinese-characters guide →Jump straight to a repair tool
Fix scientific notation
Paste or drop your CSV and expand 8.85909E+11 back to the full digit string using exact string math — no precision loss.
Restore leading zeros
Pick the column and the target width — 501 becomes 00501 again across the whole file in one click.
Fix broken characters
Reverse mojibake like é and “ automatically, including files that were mis-encoded twice.
CSV ⇆ TSV converter
Convert between comma, tab, semicolon and pipe delimiters, preview the table, and keep leading zeros and barcodes safe on the way out.
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