I had this problem with a customer the other day and found this on the myob site.
I don’t find the MYOB site very friendly so i thought i’d post it here.
This error occurs if a required Windows file is missing from your computer, which can occur when software is removed or upgraded. We’ve provided a tool below which fixes this issue.
Note that this tool has been created independently and provided to MYOB so we take no responsibility for its use.
To run the tool:
Click the following link (if prompted, choose to save the file to your Desktop): MAPI Fixit Tool.
Depending on your web browser and its settings, clicking this link may automatically open the ZIP file as shown in the following step.
If the ZIP file doesn’t automaticallly open, double-click the downloaded ZIP file to open it. You’ll see it contains a single file called CheckMAPI.VBS
Double-click the CheckMAPI.VBS file to open the tool.
Follow the on-screen prompts to run the tool and fix your issue.
If for any reason you need to undo the changes made by this tool, simply double-click the downloaded CheckMAPI.VBS file to run the tool again. You’ll then be able to restore your original Windows settings.