Excel Performance Problems

How to Fix an Excel Workbook That Doubled in File Size

Muhammad Talha Sep 30, 2026 869 views

Question details

The user's Excel workbook unexpectedly doubled in file size and began opening in two separate worksheets or windows. The user needs to identify the cause and restore the workbook to its original, manageable size.

How to Fix an Excel Workbook That Doubled in File Size

Product: Microsoft Excel
Device & OS: not provided
Scenario: Editing a shared workbook, applying formatting, or recovering a file after an unexpected application crash.
Observed behavior: The Excel file size increases exponentially or doubles, and the workbook opens multiple windows (e.g., File:1 and File:2) simultaneously.

Before you start

Create a copy of your bloated Excel workbook as a backup before attempting any cleanup or repair steps to prevent accidental data loss.

Solution 1Recommended

Clear Excess Formatting and Unused Cells

Deleting unused rows and columns removes invisible formatting that artificially inflates the file size.

Excel often retains formatting for rows and columns long after the data has been deleted. If a user accidentally formats an entire column instead of a specific range, Excel considers millions of empty cells as 'active', causing the file size to skyrocket.

Find the last used cell

Press Ctrl + End on your keyboard to locate the furthest cell Excel considers active. If it is far below or to the right of your actual data, you have excess formatting.

Highlight and delete empty rows

Select the first empty row below your actual data. Press Ctrl + Shift + Down Arrow to highlight all rows to the bottom, right-click the selection, and choose 'Delete'.

Highlight and delete empty columns

Select the first empty column to the right of your data. Press Ctrl + Shift + Right Arrow to highlight all columns to the edge, right-click, and choose 'Delete'.

Save and verify

Save the workbook immediately. Close and reopen the file to verify that the file size has returned to normal.

Clear Formatting Alternative: You can also use the 'Clear All' tool under the Home tab (Editing group > Clear > Clear All) on the unused rows and columns before saving.

Solution 2

Repair a Corrupted Workbook

Unexpected shutdowns or crashes can corrupt the file structure, leading to bloated file sizes and unusual behaviors like duplicate windows.

Solution 3

Close Extra Windows and Custom Views

If your workbook is opening twice, you likely saved the workspace with multiple windows open, which also contributes to file bloat.

Free Microsoft Office alternative

Easily Manage and Optimize Spreadsheets with WPS Office

Struggling with bloated files and unexpected Excel crashes? WPS Office offers a free, lightweight, and highly stable alternative. It seamlessly opens Microsoft Excel files, automatically optimizing the underlying structure to prevent unexpected file size anomalies.

1. Download WPS Office: Visit the official WPS website and install the free WPS Office suite on your device.
2. Open Your Bloated File: Launch WPS Spreadsheet and open the oversized Excel workbook.
3. Save to Optimize: Go to Menu > Save As and save the file. WPS Spreadsheet efficiently processes the XML structure, often drastically reducing the file size.

Fully compatible with Microsoft Office formats including .xlsx, .xls, and .csv.Lightweight architecture prevents unexpected file size bloating and lags.Free to download and use with a highly intuitive, familiar interface.Easily opens, repairs, and optimizes large datasets without crashing.

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Frequently Asked Questions

How do I stop my Excel file from opening in two windows?

This happens when the 'New Window' feature under the View tab is accidentally activated and the file is saved in that state. Simply close the second window (indicated by a ':2' in the title bar) and save your file. It will open normally the next time.

Does sharing a workbook increase its file size?

Yes, legacy shared workbooks track every change made by all users. Over time, this change history cache accumulates heavily, which can exponentially double or triple the file size. Disabling the sharing feature or clearing the change history resolves this.

Can an unexpected crash cause my file size to double?

Yes. An unexpected shutdown can corrupt the internal structure of the Excel file, leading to duplicated data caches, corrupted shared-workbook history, or bloated hidden formatting. Using Excel's 'Open and Repair' feature can often fix these structural issues.

Excel & Data Problems