Here are some key strategies to manage large datasets efficiently in Excel and avoid performance issues:

Data Organization:

1. Structure and Cleanse: Ensure your data is organized in a clean and consistent manner. Separate data into relevant columns with clear headings. Remove duplicates and unnecessary formatting.
2. Filter by Table: Convert your data range to an Excel Table. Tables offer built-in filtering functionality that can be more efficient for large datasets compared to manual filtering.

Formula Optimization:

1. Minimize Complex Formulas: Break down complex formulas into simpler ones whenever possible. This can improve calculation speed.
2. Avoid Volatile Functions: Limit the use of volatile functions like TODAY() or OFFSET() that recalculate on every change. Explore alternative non-volatile options.
3. Use Helper Columns: Consider using helper columns for intermediate calculations instead of complex formulas directly referencing large ranges.

Formatting and References:

1. Conditional Formatting Sparingly: While conditional formatting is powerful, use it judiciously on large datasets. Extensive formatting can slow down performance.
2. Optimize References: Reference only the necessary cells in your formulas. Avoid referencing entire columns or rows unless absolutely required.
3. Manual Calculation Mode: Consider switching to manual calculation mode. This allows you to control when recalculations occur, preventing unnecessary processing with every minor change.

Advanced Techniques:

1. Power Query (For Microsoft 365): If you're using Excel 365, leverage Power Query for data transformation and manipulation. It can handle large datasets efficiently outside the main worksheet.
2. Consider External Databases: For truly massive datasets, explore linking Excel to external databases like SQL Server. This can offload processing from Excel and improve performance.

Additional Tips:

1. Upgrade Hardware and Software: Ensure you have sufficient RAM and processing power on your computer to handle large Excel files. Consider upgrading if necessary.
2. Simplify Workbooks: Break down large workbooks into smaller, more manageable files. This can significantly improve performance.
3. Save as .xlsx: Save your workbooks in the newer .xlsx format for better performance and file size optimization compared to the older .xls format.

By following these strategies, you can effectively manage large datasets in Excel and minimize performance issues, allowing you to work more efficiently with your data.