# Openpyxl Common Issues

> Sub-skill of openpyxl: Common Issues.

- Skill: `vamseeachanta/openpyxl-common-issues` (Agent Skill)
- Install (CLI): `npx skillmds@latest add vamseeachanta/openpyxl-common-issues`
- Raw SKILL.md: https://api.skillmd.com/api/skills/vamseeachanta/openpyxl-common-issues/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: vamseeachanta (https://skillmd.com/u/vamseeachanta)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/vamseeachanta/openpyxl-common-issues

---


# Common Issues

## Common Issues


#### 1. Formula Not Calculating

```python
# Problem: Formulas show as text, not calculated
# Solution: Ensure proper formula format

# DO: Use equals sign and proper cell references
ws['A1'] = '=SUM(B1:B10)'

# DON'T: Use string that looks like formula
# ws['A1'] = 'SUM(B1:B10)'  # Missing =

# Note: Formulas are calculated when Excel opens the file
```

#### 2. Large File Performance

```python
# Problem: Memory error with large files
# Solution: Use streaming modes

# For writing
wb = Workbook(write_only=True)

# For reading
wb = load_workbook('file.xlsx', read_only=True, data_only=True)
```

#### 3. Style Not Appearing

```python
# Problem: Styles don't appear in Excel
# Solution: Ensure style is properly applied

# DO: Apply fill with fill_type
fill = PatternFill(start_color="FF0000", fill_type="solid")

# DON'T: Missing fill_type
# fill = PatternFill(start_color="FF0000")  # Won't show
```