MYOB AR - Email not sent - Unsupported Outlook Version - asking to switch to Outlook Classic

Ok I can email my invoices via MYOB but it is not my preferred option as I am unhappy with being pushed in this direction.

Our customers need to be able to follow up with us via email and not via MYOB AI.

And then there is the push for the online payments so MYOB can put a surcharge on our invoices.

Sooooo disappointing. :(

Hi There

I am having a similar issue with email not going through outlook (we are still using the outlook classic version) on windows 11. Account Right desktop with file online.

Unfortunately emailing directly from account right online browser version is not an option as our time billing invoices are not supported. 

Have tried checking the outlook app default setting but not seeing anything there.

Would appreciate any help.

Many Thanks

Thanks for your reply.

We have trialled the option of sending emails directly from AccountRight, but unfortunately, it doesn’t meet our needs. We frequently need to CC individual remote staff members on invoice emails, and find this process much more efficient and flexible when using Outlook rather than MYOB’s built-in email system.

Additionally, we have multiple users accessing the same online MYOB file and sending emails via Outlook without any issues. This appears to be isolated to a single computer, which suggests a localised issue rather than a broader compatibility problem.

Given this, we would prefer to continue using Outlook and would appreciate your assistance in resolving the error we're experiencing with the New Outlook version.

Looking forward to your guidance.

Ok so I have switched back to classic - no change and now I have uninstalled the new outlook and still no joy -  so any other suggestions would be greatly appreciated.

Thanks for your advice Mike_James​ - we have incorporated the office repair solution into our Email troubleshooting help topic.

Adrian

Hi Caitlin_G​ - thanks for the question.

If your AccountRight company file is online, one solution would be to send your emails directly from AccountRight. This eliminates the need for Outlook, and gives you several advantages over Outlook emails, like tracking delivery status and being able to send automatic invoice reminders.

If this sounds like a viable solution, here's a help topic all about it.

I hope this helps!

Adrian

Hi There

This is the error code

System.InvalidCastException

Message:

Unable to cast COM object of type 'Microsoft.Office.Interop.Outlook.ApplicationClass' to interface type 'Microsoft.Office.Interop.Outlook._Application'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{00063001-0000-0000-C000-000000000046}' failed due to the following error:

Interface not registered (Exception from HRESULT: 0x80040155).

Many Thanks

Caitlin_G​ ChrissyK1​ : ChatGPT explains in more detail (point 2 does not apply here):

Microsoft's New Outlook (the redesigned version for Windows and Mac) is unsupported by many third-party software programs — especially email-sending add-ins or integrations — because of major architectural and API changes compared to Classic Outlook (Win32 desktop version). Here's a breakdown of why:

🔧 1. New Outlook uses a web-based architecture

• New Outlook is built on the same web technology as Outlook for the web (OWA).
• It lacks full access to the COM/VSTO (Visual Studio Tools for Office) APIs that most traditional Outlook add-ins and integrations rely on.
• Many software tools were built using COM-based plugins, which only work with Classic Outlook.

🧩 2. Limited or no support for legacy add-ins

• Add-ins created for Classic Outlook don’t work in New Outlook unless they're re-developed as Outlook Web Add-ins using Office.js (Microsoft's JavaScript-based API).
• These modern add-ins are sandboxed, meaning they have limited access to local system resources and other Office applications.

📭 3. MAPI & Extended MAPI not supported

• Many third-party apps (e.g., accounting tools, CRMs, backup software, etc.) send emails using MAPI (Messaging Application Programming Interface).
• New Outlook doesn’t support MAPI or Extended MAPI, so apps that use these APIs can't interact with it.
• Users will see errors or missing functionality when trying to send mail via New Outlook.

🧪 4. Feature parity is still incomplete

• Microsoft is gradually adding features to New Outlook but many are still missing or limited:
  • No support for .PST files
  • No support for POP accounts
  • No scripting or macros/VBA
  • No custom forms or custom UI extensions

I used Mike's thought on ChatGPT and attempted to get AI to help me with my issue - For anyone else following along here is what AI had to say to the error message. 

This MYOB error occurs because New Outlook (Windows version) is not yet supported by MYOB for sending emails. MYOB relies on MAPI (Messaging Application Programming Interface), and the New Outlook for Windows doesn't support MAPI.

🔧 Fix: Switch to Classic Outlook

To resolve this issue, you need to switch back to Classic Outlook, which does support MAPI and is compatible with MYOB.

✅ Steps to Switch Back to Classic Outlook:

Open Outlook.

In the top-right corner, locate the toggle that says:

"New Outlook" or "Try the New Outlook"

Disable the toggle (slide it off).

You may see a message: “Switching will restart Outlook.”

Click “Switch” to revert to Classic Outlook.

Once Classic Outlook reopens, try resending the email from MYOB.

🧠 Why This Happens:

New Outlook (as of now) is a modern, stripped-down version that lacks support for traditional Windows COM and MAPI protocols.

MYOB depends on those protocols to send emails directly through Outlook.

💡 Alternative Workarounds (if switching isn’t possible):

If you're stuck using New Outlook or you're on Outlook for Web or Mac, here are a few alternatives:

Use MYOB’s built-in email option (if available).

Export invoices as PDFs and manually attach them in Outlook.

Set up SMTP email settings in MYOB to send via another service like Gmail or Outlook SMTP (this requires more setup and isn't available in all MYOB versions).

Hi Caitlin_G​ the option to switch back to classic should be available up to some time in 2028.