What the message points to
The first row defines the columns. A misspelled heading, extra whitespace, wrong delimiter, or a header copied from another CSV type can prevent Shopify from recognizing the fields. Check the actual header row before changing product data.
Which headers are required?
Title is the only required column. An absent URL handle can be generated from the title.
Include both Title and URL handle so Shopify can identify the product.
Include URL handle. When updating variant-related columns such as SKU, also preserve the matching Option1 name and Option1 value columns; omitting dependent option data can change variants.
A missing Title header
This minimal update example has product names, but its first heading is not Shopify's Title column.
Product title,URL handle
Tee,tee
Catalog Precheck reports H001 for the missing Title header and warns that Product title is unknown.
Title,URL handle
Tee,tee
Only rename the column if its values really are product titles. Keep a copy of the original file.
How to fix the header safely
- 01
Confirm this is a Shopify product CSV, not an inventory or another app's export. Open a copy as UTF-8 comma-separated text.
- 02
Inspect the first row, including spelling and trailing spaces. Match each heading to the data beneath it; do not rename unrelated values just to silence an error.
- 03
Choose create or update before deciding which columns are required. For updates and variants, retain the handle and any dependent option columns.
- 04
Save a new CSV, check it locally, then review Shopify's current sample and import settings before importing.
Check the header locally
Blank value or omitted column? Review the update
When updating matching products with overwrite selected, a blank non-required column can clear its saved value; leaving that optional column out preserves its saved value. If overwrite is off, matching handles are ignored. This exercise compares those two Vendor edits.
The unchanged public source has two products and four variants. Vendor is Harmony Publishing for the digital product and Acme for the perfume. One edited file keeps all 57 columns and blanks only those two nonempty Vendor cells. The other removes just Vendor, leaving 56 columns. Prices, handles, options and every other retained cell stay the same; all three pass current update-mode Validator checks.
| URL handle | Original Vendor | Column kept | Column omitted |
|---|---|---|---|
digital-product-the-history-of-rock-music | Harmony Publishing | (empty cell) | (no Vendor column) |
example-perfume | Acme | (empty cell) | (no Vendor column) |
The source is an unchanged four-variant subset of Shopify’s official CSV retrieved on September 28, 2026. Both edits are controlled derivatives for practice, not exports from your store. Official CSV download (current version)
- 01
Choose one edited example below, load it into Compare, keep “I’m not sure” and run the comparison. Both cases should match two products and four variants.
- 02
With overwrite on, blank Vendor produces two high-risk “Non-empty becomes blank” findings. Omitting Vendor produces no findings in this example because that column is not compared. With overwrite off, neither case produces findings for the matching handles.
- 03
Download the complete report, then choose the other example and load it again. Switching examples clears the previous files and results. For your own update, compare a fresh target-store export with the edited file and review every retained field before a small trial import.
Only the two public sample files are fetched. Comparison runs in your browser; file contents are not uploaded. No account or test store is needed for this exercise.
No findings does not prove an import is safe. Compare checks selected fields in two files, not the live store. Other retained columns and their blanks may still overwrite store data. This optional Vendor example does not cover required fields, inventory CSVs, linked options or new-product defaults.
Official import guidance reviewed on October 7, 2026: Overwrite rules and dependencies
Sources checked: 28 September 2026. Shopify: common import issues · Shopify: current product CSV format
Catalog Precheck is an independent tool and is not affiliated with Shopify.