The Northern Irishman was in the final pairing with Norway's Viktor Hovland, but neither could get much going on Sunday.
Instead, it was Australia's Cameron Smith who lifted the Claret Jug at the Home of Golf.
Now, McIlroy will be playing golf in Scotland again in July with this year's Genesis Scottish Open.
The four-time major winner was announced to the field of the co-sanctioned DP World Tour and PGA Tour event on Tuesday.
“I’m pleased to be able to add the Genesis Scottish Open to my schedule again this season. The Scottish fans have always been very supportive of me and it would be great to win a title in the home of golf," McIlroy said in the announcement.
He joins an impressive roster of names set to make the trip to the Renaissance Club in North Berwick, Scotland for 13-16 July.
World No. 1 Scottie Scheffler, Matt Fitzpatrick, Justin Thomas, and defending champion Xander Schauffele were a few of the names already confirmed. European Ryder Cup stars Tommy Fleetwood and Tyrrell Hatton are also committed to the event, as is home-crowd favourite Robert MacIntyre.
The tournament is played a week prior to The Open. This year the season's final major is being played at Royal Liverpool Golf Club in Hoylake, England.
McIlroy won the Open Championship in 2014 when the tournament was held at Royal Liverpool.
So far this season, he has one win on the PGA Tour and one on the DP World Tour.
July's Scottish Open will mark his eighth appearance at the tournament.