Fix Excel and Outlook Freezing When Sending a Workbook as an Attachment
Question details
Excel and Outlook applications become completely unresponsive when trying to share a file via email.
- Product
- Excel 365, Outlook 365
- Device & OS
- Windows
- Scenario
- Using the 'File > Share > Email > Send as Attachment' feature in Microsoft Excel to email a workbook.
- Observed behavior
- A blank Outlook message opens with the attachment, but both Excel and Outlook remain blocked and unresponsive until the email is manually sent or discarded.
Ensure you have saved your current Excel workbook locally to prevent any data loss before forcing the applications to close or making system changes.
Update and Repair Microsoft 365
Running a system repair on your Microsoft 365 installation can resolve underlying MAPI integration conflicts between Excel and Outlook.
The freezing behavior is often related to how Microsoft Office handles the Windows Messaging Application Programming Interface (MAPI). Repairing the Office suite can refresh these background integrations.
Press the Windows key + I to open Settings, then navigate to 'Apps' > 'Installed apps' (or 'Apps & features').
Scroll down to find 'Microsoft 365' in the app list. Click the three dots (or right-click) and select 'Modify'.
Select 'Online Repair' from the dialog box and click 'Repair'. Follow the on-screen instructions and restart your computer once the process finishes.
Verify Outlook is the Default Mail Application
Windows must recognize Outlook as the primary default mail handler to properly process the 'Send as Attachment' command from Excel without hanging.
Disable Conflicting Outlook Add-ins
Third-party add-ins in Outlook can interrupt the communication process between Excel and the new message window, causing a deadlock.
Switch to WPS Office for Seamless Document Sharing
If Microsoft Excel and Outlook continue to freeze due to MAPI integration bugs, consider switching to WPS Office. It provides a lightweight, highly compatible spreadsheet editor that allows you to easily email your workbooks without application lockups.
- 1. Download and Install: Download WPS Office from the official website and run the quick installation.
- 2. Open Your Spreadsheet: Launch WPS Spreadsheets and seamlessly open your existing .xlsx files.
- 3. Share via Email: Go to the Menu, select Share > Email, and instantly send your file without application freezes.
Frequently Asked Questions
Why does Excel lock up when opening an Outlook email window?
This happens because Excel pauses its operations and waits for the Windows MAPI (Messaging Application Programming Interface) process to finish handling the email. Until the new Outlook message is either sent or closed, Excel remains in a blocked, unresponsive state.
Is there a quick workaround to avoid the freeze?
Yes. Instead of using the 'Send as Attachment' feature inside Excel, save your workbook to your computer. Then, open Outlook independently, create a new email message, and manually attach the saved Excel file.
What should I do if updating and repairing Microsoft 365 doesn't work?
If local troubleshooting fails, the issue might be a specific software bug requiring Microsoft's attention. You should submit a support request to Microsoft including your Windows version, Office version, system event logs, and the exact steps you take when the freeze occurs.
