ExtendInsights can automatically update Excel workbooks stored in OneDrive or SharePoint based on a schedule.
To perform a scheduled update, ExtendInsights uses the Microsoft Graph API to access and write data to the workbook in the cloud. Because this process relies on Microsoft’s online Excel services, workbook size, complexity, and design can affect scheduling performance and reliability.
How Scheduled Writes Work
During a scheduled run, ExtendInsights uses Microsoft Graph to:
Access the workbook stored in OneDrive or SharePoint.
Open an online workbook session.
Write the latest data to the designated worksheet.
Save the updated workbook.
This process does not require Excel desktop to be open. However, the workbook must be accessible through Microsoft’s online services and remain within Microsoft’s supported limits.
Microsoft also notes that opening large workbooks through its Excel API can take longer and may result in timeout-related behavior. Learn more about Microsoft Graph Excel API best practices.
Keep the Workbook Below 100 MB
Microsoft supports workbooks up to 100 MB when they are stored in SharePoint Online and opened in a browser.
If a workbook exceeds this limit:
Microsoft’s online Excel services may be unable to open it.
ExtendInsights may be unable to write scheduled data to it.
The scheduled run may fail or return an error.
The workbook may still open in Excel desktop even when it cannot be opened online.
➡️ See Microsoft’s documentation about file size limits for workbooks in SharePoint.
💡 Recommendation: Keep scheduled workbooks well below 100 MB whenever possible. A workbook close to the limit may still experience performance problems because file size is only one factor.
Review Workbook Complexity
A workbook under 100 MB can still be difficult for Microsoft’s online services to process.
Power Pivot and Data Models
Workbooks containing large Power Pivot or Data Models may require considerably more memory than their stored file size suggests.
These workbooks may take longer to open, calculate, or save during a scheduled update.
Complex Formulas and Workbook Features
The following features can increase workbook-processing time:
Large PivotTables
Data Models
Linked workbooks
Volatile or calculation-intensive formulas
Large numbers of formulas
High row counts
Columns containing many unique values
Charts and other visual elements connected to large datasets
The effect depends on the workbook’s overall size, structure, and available Microsoft 365 resources.
Recommended Approach: Separate the Source and Analysis Files
For more reliable scheduled updates, use two Excel files:
A lightweight source workbook that ExtendInsights updates
A separate analysis workbook containing your reports, calculations, and visualizations
Source Workbook
Use ExtendInsights to write scheduled data to this file.
Keep the source workbook simple:
Store the raw data retrieved by ExtendInsights.
Avoid complex formulas and calculations.
Avoid Power Pivot models and dashboards.
Limit charts, PivotTables, and other visual elements.
Include only the data required by the analysis workbook. Keeping your source data in one file and your report in another makes sure the scheduler runs smoothly and reliably — while letting you control your data without messing up your analysis.
Analysis Workbook
Use this file for reporting and analysis.
Connect it to the source workbook using Power Query. You can then:
Transform and combine data
Create calculations
Build PivotTables and charts
Maintain dashboards
Connect data from multiple source files
Because ExtendInsights does not write directly to the analysis workbook, its formulas, visualizations, and Data Models do not add complexity to the scheduled write.
Example Workbook Structure
File | Purpose | Recommended complexity |
SalesData_Source.xlsx | Receives scheduled data from ExtendInsights | Lightweight workbook containing source data |
SalesDashboard.xlsx | Retrieves the source data through Power Query | Reporting workbook containing formulas, PivotTables, charts, or Power Pivot |
This structure allows ExtendInsights to update the source data while users maintain a more advanced reporting workbook separately.
Additional Recommendations
For more reliable scheduled runs:
Store the workbook in OneDrive for Business or SharePoint.
Confirm that ExtendInsights has the required Microsoft permissions.
Keep the source workbook well below the 100 MB limit.
Schedule only the data your report requires.
Remove unused worksheets, formulas, formatting, and data.
Avoid changing worksheet names or scheduled report configurations without reviewing the associated schedule.
Run the report manually before scheduling it.
Monitor the first scheduled run to confirm that the workbook updates successfully.
Choose a schedule frequency appropriate for how often the underlying data changes.
Use separate source files when a single workbook contains several large datasets.
Managing File Versions
OneDrive and SharePoint may create a new version whenever a scheduled update changes the workbook. Over time, version history can increase storage consumption.
Your Microsoft 365 administrator can configure how many versions a SharePoint document library retains. Before changing version settings, consider your organization’s retention, audit, and recovery requirements.
➡️ See Microsoft’s guide to enabling and configuring versioning for a list or library
Need Help?
If you need help restructuring a workbook or troubleshooting a scheduled update:
💬 Use the in-app messenger.
🔍 Visit the CloudExtend Help Center.
✉️ Email cloudextend-support@celigo.com.
When contacting Support, include the workbook size, storage location, schedule frequency, complete error message, and screenshots when available.