This error was fixed by going to the following path and renaming “MSMAPI32.DLL” to “MSMAPI32.old”. After that the program worked normally. The path the DLL on Windows 10 is “C:\Program Files (x86)\Common Files\system\MSMAPI\1033”.
Had a similar issue with the same customer here were getting the no default mail program. The issue started when Office 2019 was installed while Office 2010 was still installed. When 2010 got removed is when we got this issue. Going into the Control Panel >> Programs and Features. Select the Office install and hit “change”, but select “Repair”. We did the quick repair and this didn’t seem to fix the issue; however, after a restart everything was working the way it should.
The next computer got the “MSMAPI” error again. I went into the control panel and ran a quick repair on the Office install, but this didn’t fix the issue. What fixed the issue was making sure Outlook was the default program and the .eml extension was set to Outlook.