Summary  
This chapter demonstrates how to wrap lookup operations in an error‐handling function to catch runtime errors and return custom fallback messages, and how to leverage an AI assistant to automate code modifications and explain formulas.

General domain of usage  
Spreadsheet data processing

After creating the lookup, some rows return errors because certain SKUs do not exist in the Catalogue.

Before continuing, you need to handle these errors properly.




Errors like #N/A break calculations. Functions such as SUM or SUMIFS will not work correctly if errors are present.

Replacing errors with clear text keeps your data usable and easier to understand.

Why Errors Must Be Fixed


Use Copilot in Edit mode to update the lookup formulas.

Ask it to modify the formulas so that missing values return a clear message like 'Missing SKU' instead of an error.

Copilot wraps the existing formula with error handling and updates the entire column.

Replace Errors with Copilot


Check that all error values are replaced correctly.

Make sure valid rows still return correct results and only missing entries show the text flag.

Verify the Result


You can ask Copilot to explain the updated formula.

This helps you understand how error handling works without writing it manually.

Learn from the Formula

Discover how to use Excel with Copilot to solve real business problems. Explore practical workflows that turn messy data into structured, reliable systems. Learn how to build models, automate calculations, and generate insights without memorizing formulas. Understand how to guide Copilot, validate its output, and keep full control over your logic.

Explore the core setup and habits for working with Copilot in Excel. You configure your environment, learn how to write clear prompts, and apply safe workflows before using Copilot on real data. You focus on testing, verifying results, and protecting your files. These skills help you avoid mistakes and use Copilot with confidence further.

Focus on turning messy, inconsistent datasets into clean and usable data. You standardize headers, split combined fields, fix mixed formats, and remove duplicates using Copilot. Consider real-world scenarios and apply structured workflows to clean data safely.

Discover using Copilot to work with clean data and turn it into insights. You extract values, connect multiple datasets, handle errors, and build dynamic summaries. Learn to describe tasks in plain language while Copilot generates and applies the formulas.

Learn how to present data in a clear and interactive way. Create PivotTables, add slicers, build charts, and apply conditional formatting to highlight key insights. Combine all elements into a structured dashboard and use Copilot to support analysis, formatting, and presentation. 

Build a forecasting model using assumptions, pricing scenarios, and 12-month projections. Test different outcomes, guide Copilot through complex logic, and turn your analysis into a clear, decision-ready recommendation.

Turn your work into a reusable, product-like spreadsheet. Clean raw data, combine multiple sources into a single system, build automated reports, and package everything into a polished template with instructions that anyone can use.

Handle Errors Cleanly with IFERROR