The Northern Irishman was the early pacesetter on the Majlis course, a sizzling first round 63 putting him two strokes clear of the field.
But he never recaptured Thursday's sparkle and the 24-year-old entered Sunday's final round two shots adrift of eventual winner Stephen Gallacher.
Gallacher blundered with successive bogeys on the first two holes to put McIlroy ahead, but that lead proved short-lived as the world number six registered four bogeys between the seventh and 13th to slip back into the pack.
"Anything that could go wrong did - okay, I hit a couple of loose drives, but I didn't (get) away with them, stuff like that," McIlroy told reporters.
"I didn't get a couple of putts to go. I was struggling to read them for some reason, so I got (caddy) JP (Fitzgerald) to read them for me on the back nine and holed a couple more.
"When the greens get this firm they change colour a little bit and it was very hard to see. Everything I read was straight even though it wasn't - I just couldn't see any movement at all."
McIlroy's winless streak on the European Tour - his last victory was at 2012's DP World Tour Championships in Dubai, although he did triumph at December's Australian Open - would not be troubling for most golfers.
But for McIlroy, who won his first tour title as a teenager and was a double major champion by the age of 23, it represents a steep decline from the glories of 2012.
That year he became only the second golfer to top the money lists in both Europe and the United States in the same season as he become world number one.
Since then McIlroy has found it harder going, although Dubai's joint-ninth placing means he has made the top 10 in five of his past six tour events and Desert Classic champion Gallacher had no doubt his playing partner would again challenge for golf's top honours.
"His first round was unbelievable," Gallacher told reporters. "I shot 66 and it felt like 75. His ball flight is just phenomenal. I've never played with anyone who flights it as good as him. I think he'll soon be contending with Tiger (Woods) for the number one spot. He's a class player."
- Sports & Recreation
- Stephen Gallacher