How to Review an Inherited Workbook

How to Review an Inherited Workbook

Inherited workbooks are risky because you are responsible for a file you did not build.

You may not know which sheets matter, which formulas are critical, where assumptions are stored, or whether the workbook contains hidden problems.

Start with a copy

Never begin by editing the original workbook. Save a copy first.

Use a file name such as:

Inherited_Model_Review_Copy.xlsx

This protects the original file while you investigate.

Step 1: Understand the purpose

Before reviewing formulas, understand what the workbook is supposed to do.

Ask:

• What is the workbook used for?
• Who uses it?
• What decisions depend on it?
• Which sheets are inputs?
• Which sheets are outputs?
• How often is it updated?

Step 2: Map the workbook

Create a simple map of the workbook:

• input sheets
• calculation sheets
• output sheets
• data import sheets
• lookup tables
• hidden sheets
• old backup sheets.

This helps you understand the flow of information.

Step 3: Check hidden content

Inherited workbooks often contain hidden sheets, hidden rows, or hidden columns.

Review them before relying on the file. Hidden areas may contain old assumptions, sensitive information, or formulas still feeding the report.

Step 4: Find external links

Check whether the file depends on other workbooks. External links can make an inherited file difficult to maintain because the source files may be missing.

Step 5: Review formulas

Look for:

• formula errors
• inconsistent formulas
• overwritten formulas
• hardcoded values
• formulas pointing to old sheets
• formulas linked to external files.

Start with the final output sheets and trace backwards.

Step 6: Identify assumptions

Find where assumptions are stored. In a good workbook, assumptions are clearly labeled and separated from formulas.

In a risky workbook, assumptions may be hidden inside formulas.

Step 7: Check data quality

If the workbook uses imported data, check for duplicates, blank rows, text numbers, text dates, and inconsistent headers.

Step 8: Create an issue log

Document what you find. Include:

• sheet
• cell or range
• issue
• risk level
• recommended action
• status.

This creates a clear review trail.

Conclusion

Reviewing an inherited workbook takes time, but it protects you from relying on a file you do not fully understand.

SaferSheets helps accelerate inherited workbook reviews by scanning for hidden risks, formula issues, hardcoded assumptions, external links, and data quality problems.