Thailand's Chapchai Nirat and Simon Dyson held the joint lead midway through their second rounds, with half the field yet to take the course and more rain forecast for the weekend.
Organisers said more delays could force them to slash the event from 72 to 54 holes or to complete the fourth round on Monday. Last year, it was cut to 54 holes and still only finished on the Monday morning.
Reducing the tournament could be inconvenient for world number one McIlroy, who was tied for 29th after 12 holes of his second round and needing a high finish to confirm himself as Europe's top prize money-winner this year.
The 23-year-old, bidding to become only the second man to seal the money titles on both sides of the Atlantic in the same year, completed his first round five shots off the pace.
Watched by tennis star girlfriend Caroline Wozniacki but suffering from a cold, McIlroy made a wretched start to his second round with bogey and double bogey in his first four holes. But some razor-sharp shots got him back before he was hauled off the course for the second time, in a golf buggy with Woz-niacki sitting cosily on his lap.
Anirban moves upIndian golfers SSP Chowrasia and Anirban Lahiri completed their opening round and improved their positions before rain left them stranded midway through the second round.
Weather played spoilsport once again as more than half the field was yet to begin their second round. In fact, none of the players who played in the first session on Thursday got any action. India’s best placed players in the first round, Himmat Rai and Jyoti Randhawa, both two-under, did not get a chance to tee off.