Salesforce Inbox or Outlook Integration Add-In Error in Outlook 2013 or Outlook 2016

Overview

When Salesforce Inbox or the Salesforce Outlook Integration add-in fails to load in Outlook 2013 or Outlook 2016 with an "add-in could not be started" error, this is typically caused by a missing or incorrect Windows Registry key that controls how Microsoft Office applications access online content. The following steps explain how to create or correct the UseOnlineContent registry key to resolve the issue.
For Microsoft's official troubleshooting reference, see Troubleshoot user errors with Office Add-ins.

Step 1: Open Windows Registry Editor

1. Close Outlook.
2. Press Windows + R, type REGEDIT, and press Enter to open Windows Registry Editor.

Step 2: Navigate to the Office Internet Registry Key

Navigate to one of the following registry paths depending on your environment:

• HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Internet
• HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\<x.0>\Common\Internet

(Replace <x.0> with your Office version number, e.g., 16.0 for Office 2016 or 15.0 for Office 2013.)

Step 3: Create or Update the UseOnlineContent Key

1. Right-click the Internet folder.
2. Click New, then select:
   1. DWORD (32-bit) value if you have Outlook 32-bit.
   2. QWORD (64-bit) value if you have Outlook 64-bit.
   3. To check your Outlook bitness: In Outlook, click File > Office Account > About Outlook.
3. Right-click the new value and click Rename. Name it UseOnlineContent and press Enter.
4. Double-click the key, set its value to 2, and click OK.
5. Exit Registry Editor.
6. Reopen Outlook and test the Salesforce Inbox or Outlook Integration add-in.