Word add-in: The add-in could not be started with displayDialogAsync

Question

I'm calling Office.context.ui.displayDialogAsync() in a word add-in. The dialog displays the message "ADD-IN ERROR The add-in could not be started. Please restart all Office applications and try again." But the displayDialogAsync() callback gives the succeeded status.

The page is a https URL with the same domain. (I'm testing on localhost.)

I can open the same URL with window.open() so I know the page exist.

Anyone knows what could be the reason for the error message, or how to get better diagnostics?

What browser is used for hosting the add-in? Do you get the same result with any web browser? — Eugene Astafiev, Oct 29 '22 at 19:59
There is no information for the host version and platform. The manifest file would be useful. — Eugene Astafiev, Oct 29 '22 at 20:07
@EugeneAstafiev: Windows 11 (10.0.22621), Office 365 MSO, Word version 2210. The add-in seem to be hosted in Edge, can this be changed? — JacquesB, Oct 29 '22 at 21:16
@EugeneAstafiev: Protected mode does not seem to be an option in Windows 11? — JacquesB, Oct 30 '22 at 09:37
In Windows 11 you can set the Protected Mode configuration in Windows registry. — Eugene Astafiev, Oct 30 '22 at 10:20
I've edited the post to describe how it can be configured in Windows 11. — Eugene Astafiev, Oct 30 '22 at 10:23
@JacquesB have you tried reinstalling the Office/SharePoint Development Workload for Visual Studio? Seems like several developers resolved this error by doing this as discussed in [ADD-IN ERROR This add-in could not be started](https://stackoverflow.com/questions/53469033/add-in-error-this-add-in-could-not-be-started). — joeschwa, Nov 05 '22 at 04:13

Eugene Astafiev · Answer 1 · 2022-10-30T10:22:34.713

If you specified callback when calling the displayDialogAsync method, you may check result.error.code and result.error.message. As soon as you know what the actual error is, you can start troubleshooting, for example:

var dialog;
Office.context.ui.displayDialogAsync('https://myDomain/myDialog.html',
   function (asyncResult) {
       if (asyncResult.status === Office.AsyncResultStatus.Failed) {
            showNotification(asyncResult.error.code = ": " + asyncResult.error.message);
       } else {
            dialog = asyncResult.value;
            dialog.addEventHandler(Office.EventType.DialogMessageReceived, processMessage);
      }
});

Check out the Handle errors and events in the Office dialog box for well-known errors.

Also you may find the Troubleshoot development errors with Office Add-ins page helpful.

Also make sure that the Protected mode is turned off in Windows.

In Windows 11, Protected Mode settings are missing in Internet Options, but you still can modify them via registry editor. These settings are stored in HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones. Under Zones is a subkey for each zone, named numerically:

0 is the Local Machine zone
1 is the Intranet zone
2 is the Trusted Sites zone
3 is the Internet zone
4 is the Restricted Sites zone

Under each numerically-named key, you can create or set a REG_DWORD value named 2500 to control whether Protected Mode is enabled for the zone. Setting that value to 0 enables Protected Mode; a setting of 3 disables it.

So, to disable Protected Mode for the Internet zone, set this entry to 3:

 HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3\2500

I get the "succeeded" status in the callback and a dialog handler. — JacquesB, Oct 29 '22 at 20:32
Is Protected Mode enabled on the Internet Properties dialog window? — Eugene Astafiev, Oct 29 '22 at 20:44
In any web browser or in Windows directly. Word hosts a web browser instance for running your add-ins. — Eugene Astafiev, Oct 29 '22 at 21:27
Unfortunately this did not have any effect. Is disabling protected mode a requirement for running word add-ins? — JacquesB, Oct 30 '22 at 12:22
Did you restart the web browser or host application after disabling the protected mode? — Eugene Astafiev, Oct 31 '22 at 05:58
I even restarted the computer. Is disabling protected mode a requirement for running word add-ins? — JacquesB, Oct 31 '22 at 07:14

Word add-in: The add-in could not be started with displayDialogAsync

1 Answers1