Word couldn’t send mail because of MAPI failure: “Unspecified error”

The email client is used to handle the email request sent by an application. Microsoft Outlook or any other email client should be set as a default email client to handle the email request sent by Word.

• Go to Start and click on Control Panel or Press Windows+R keys to open the Run box. Type “control” into the “Open” field, and then hit Enter or click on Ok to launch Control Panel
• Choose Default Programs from the Control panel.
• Click on Set your Default programs option.
• Select Microsoft Outlook from the drop-down menu.
• Click on Set this program as default to set Outlook as a default mail application.

If Microsoft Outlook is already set as a default email client, then there is likely to be some other reason causing the error Word couldn’t send mail because of MAPI failure.

MSMAPI files are used to describe message services and their service providers and forms. If it used by another program or service then it may cause the error “Word couldn’t send mail because of MAPI failure”.

• Close the Word application.
• Navigate to C:\ Program Files\ Common Files\ System\ MSMAPI\ <LocaleID>
  • (LocaleID is 1033 for English versions)
• Locate and Rename MSMAPI32.dll to MSMAPI32.old.

Now open the Word application and check if the issue still exists.

Starting Outlook in Safe Mode can let you safely use it while it has encountered errors like “Word couldn’t send mail because of MAPI failure: Unspecified error”. This is helpful when you can’t open a file in normal mode because the application is crashing or there is an extension or add-in causing a problem on startup.

In safe mode, the Outllok may not open with the options provided by addins but can perform basic operations.

• Find the shortcut icon of Outlook.
• Press and hold the CTRL key and double-click the Outlook icon shortcut.
• Click Yes on the prompt to start the application in Safe Mode. Or Press Windows+R keys to open the Run box. Type “outlook/safe” into the “Open” field, and then hit Enter or click on Ok to launch Outlook in Safe mode.

• Once Outlook is open click on File > Manage Add-ins.

• Under Manage add-ins, in the Turned on column, uncheck the box for the add-in you want to turn off.

If Outlook fails to open in Safe Mode, you may be required to reinstall the application from a reliable resource.

If you are attempting to send an email with attachment more than 20MB, then you also might get the error “Word couldn’t send mail because of MAPI failure”. By default, Outlook does not send emails with attachments that exceed 20 MB, but many mail servers allow 25 MB or larger attachments. If your email server allows larger attachments, configure Outlook to send emails larger than 20 MB.

• Press Windows Key + R to open Run command, type regedit in the open field, and click Ok.

• Navigate the registry tree and go to the entry corresponding to your Outlook version:
  • Outlook 2019 and 2016: HKEY_CURRENT_USER > ­Software > Microsoft > ­Office > ­16.0 > ­Outlook > ­Preferences
  • Outlook 2013: HKEY_CURRENT_USER > Software > Microsoft > Office > 15.0 > Outlook > Preferences
  • Outlook 2010: HKEY_CURRENT_USER > ­Software > Microsoft > ­Office > ­14.0 > ­Outlook > Preferences
• Double-click the MaximumAttachmentSize value.
  • Note: If you don’t see MaximumAttachmentSize, add a registry key and value. Go to Edit, select New > DWORD Value, enter MaximumAttachmentSize, and press Enter.

• In the Value data text box, enter the desired attachment size in KB(KiloByte).
• Select OK and Close the Registry Editor.

If you have start receiving the error message “Word couldn’t send mail because of MAPI failure” after the installation of an Office application, try to fix the problem by repairing the Office installation.

• Go to Start and click on Control Panel.
• From Category view, under Programs, click on Uninstall a program. or Press Windows+R keys to open the Run box. Type “appwiz.cpl” into the “Open” field, and then hit Enter or click on Ok to launch Programs and Features.
• Select the Office product you want to repair, and then click Change.
• Depending if your copy of Office is Click-to-run or an MSI-based install, do the following for your Office installation type:
  • Click-to-Run installation type: In How would you like to repair your Office Programs, select Quick Repair to detect and replace corrupted files and then select Repair.
  • MSI-based installation type: In Change your installation, select Repair and then click Continue.
• Follow the remaining instructions on the screen to complete the repair.

Check if Error “Word couldn’t send mail because of MAPI failure” is fixed after restarting the device

Multiple Office installation can also cause “Word couldn’t send mail because of MAPI failure”. Consider removing Microsoft Office versions installed from the device and check again.

Uninstall Office from the Control Panel

• Press Windows Key + R to open Run command, type appwiz.cpl and click Ok. Or Open Control Panel –>Programs
• Right-click on the Microsoft Office product, and choose Uninstall.
• Follow the instructions on the screen.

Uninstall Office using Microsoft Easy Fix Tool

Try running Microsoft Easy Fix tool to completely remove Office from the device.

Reference: Microsoft Article for uninstalling Office

Consider checking after restarting the device.

We’ve compiled all the resolutions and workarounds verified by the experts to fix the mentioned error. These resolutions and workarounds helped the users to fix the error on their system. Try implementing these resolutions on your computer and if the preceding suggestions fail to solve the error, please feel free to Ask an Expert.