An accountant had just upgraded a customers PC (vista) from myob v16 to v17

So windows mail suddenly stops sending myob invoices (myob has a “send to” -> email option)… it gives a vague mapi error (something about mapi32.dll)

It seems to be a common problem (and might also apply to XP).

Some people suggest a solution is to install Mozilla Thunderbird as an alternative email client (to fix this problem).

I install thunderbird, and myob can send emails again.

A few weeks later, the same customer gets upgraded to myob “v17.5”

And now thunderbird and windows mail won’t work.

The accountant tries to re-install Thunderbird, but doesn’t get very far, as the reinstallation has problems.

I’m passing by, so I stop and take a quick look.

I try uninstalling thunderbird (no problem)

I restart, and then run the thunderbird setup… it completes, but complains about not being able to overwrite mapiproxy.dll

I try the quick way out: rename mapiproxy.dll to something like mapiproxy.lld

I reinstall thunderbird, and this time it doesn’t complain.

I try sending from myob, and its working. Awesome!

I then start thunderbird, to show the customer the send mail folder (with the mail I just sent)… but its not there!

It turns out it got sent by vistas windows mail (it had become the default email client at some point).

I make thunderbird the default email, then send another invoice.

This time it is sent via thunderbird.

But it is strange that windoze mail has started working again.

After doing some research, it turns out that myob might be using extended mapi (and thunderbird and vista mail use simple mapi)… so it looks like many potential problems in the future.