Excel Performance Problems

Fix Excel Workbooks Opening Slowly After Version 2405 Update

WPS Content Manager Sep 28, 2026 869 views

Question details

Users need to restore normal loading times for large macro-enabled Excel workbooks that have become extremely slow to open following a recent Office update.

How to Fix Excel Workbooks Opening Slowly After Version 2405 Update

Product: Microsoft Excel
Device & OS: not provided
Scenario: Opening large, complex Excel files stored on SharePoint that contain VLOOKUPs, PivotTables, or macros.
Observed behavior: After updating to Microsoft 365 Apps version 2405, large workbooks take an excessive amount of time to open (sometimes over an hour) and cause unusually high CPU usage.

Before you start

Before rolling back your Microsoft 365 installation, save any open work and close all Office applications to ensure the update process runs smoothly without data loss.

Solution 1Recommended

Roll Back Microsoft 365 Apps to a Previous Build

Reverting your Office installation to an earlier, stable build (such as 16.0.17531.20152) instantly resolves the extreme loading times introduced in version 2405.

This solution uses the Office Click-to-Run client to downgrade your current installation. You must disable automatic updates first so the system does not immediately reinstall the problematic version.

Disable automatic updates

Open Excel (or any Office app), navigate to File > Account, click the 'Update Options' button, and select 'Disable Updates' from the dropdown menu.

Open Command Prompt as administrator

Press the Windows key, type 'cmd' into the search bar, right-click on 'Command Prompt', and select 'Run as administrator'.

Run the rollback command

Type the execution command for the Click-to-Run client to revert to a stable version. For example: "C:\Program Files\Common Files\microsoft shared\ClickToRun\officec2rclient.exe" /update user updatetoversion=16.0.17531.20152 and press Enter.

Wait for the process to complete

An Office update window will appear and download the specified previous version. Once completed, reopen your complex Excel file to verify it now loads in seconds rather than hours.

Roll Back Microsoft 365 Apps to a Previous Build

Monitor Microsoft Update History: Keep an eye on the official Microsoft 365 Apps update release notes. Once Microsoft officially patches this SharePoint workbook performance bug in a future build, you can safely re-enable automatic updates in your Account settings.

Free Microsoft Office alternative

Try WPS Office for Fast and Reliable Spreadsheet Performance

If Microsoft 365 updates frequently disrupt your workflow with performance bugs, consider switching to WPS Office. It is a free, highly optimized alternative that effortlessly handles large datasets, complex formulas, and macros without unexpected loading delays.

1. Download and install: Get WPS Office for free from the official website and complete the quick installation process.
2. Open your large workbook: Launch WPS Spreadsheets, click 'Open', and select your complex SharePoint or local Excel file.
3. Experience fast processing: Edit your data, refresh PivotTables, and run macros instantly without the severe loading delays found in the recent Microsoft update.

Highly compatible with Microsoft Excel (.xlsx, .xlsm, .csv) formats.Lightweight architecture ensures fast startup times and low CPU usage, even for large workbooks.Stable and reliable performance when processing VLOOKUP formulas, macros, and PivotTables.Familiar tabbed user interface that requires zero learning curve for seamless migration.

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Frequently Asked Questions

Why is my Excel file taking over an hour to open?

If you recently updated to Microsoft 365 Version 2405, a known performance bug causes massive delays when opening large, macro-enabled workbooks stored on SharePoint, particularly those containing extensive VLOOKUPs and PivotTables.

Will I lose my data if I roll back Microsoft Office to a previous version?

No, rolling back the Office application build only affects the software version itself. Your saved workbooks, macros, custom settings, and SharePoint data remain completely safe and unaffected.

Does this performance issue affect all Excel files?

The issue primarily impacts large and complex workbooks. Users report the most severe loading times and high CPU usage with files that rely heavily on external worksheet links, macros, and intensive formula calculations.

When should I turn Excel automatic updates back on?

You should re-enable updates only after Microsoft officially confirms they have released a patch that resolves the SharePoint workbook loading issue in a post-2405 build. You can track these fixes in the Microsoft 365 release notes.

Excel & Data Problems