This is getting to the point where it is having an adverse impact on my business. The problem has been ignored by MYOB for several years now in spite of numerous complaints.
The export of cards from MYOB cards to Outlook slows down as it progresses until it is so slow it finally stops working usually after 12 - 24 hours. I have 1600 contacts and it is now impossible to synchronise them with Outlook, it just doesn't work.
I suspect no one at MYOB has tried to synchronise this many contacts. If you have only 400 contacts, it is doable even though by the 400th contact the speed is probably 1/10 of that for the first few contacts. It slows down further to less than 1% and eventually stops at about 1100 contacts.
I have the latest MYOB 2015.4 software and Outlook 2016 although this has been a problem for years with different versions of MYOB and Outlook.