Rashawn Rembert scored a career-high 18 points and Lester Wilson added 13 points on 5-of-19 shooting with 11 rebounds for ETSU (2-5). Its halftime point total was the fewest for a half in the nearly 27-year-old Smith Center.
Reggie Bullock added 10 points for the Tar Heels, who won their second straight since an ugly loss at No. 1 Indiana.
UNC had this past week off for final exams, but the Tar Heels sure didn't get much of a test from the largely noncompetitive Buccaneers.
North Carolina finished with a season-high 30 assists on its 31 field goals and forced 22 turnovers. During a stretch of roughly 14 minutes in the first half, the Tar Heels held ETSU to 1-of-17 shooting.
Point guard Marcus Paige, who missed last week's win over UAB with a jammed left shoulder, was back in the starting lineup and had seven assists in 21 minutes.
And fellow freshman Joel James made his second straight appearance as the fifth starter. His first came during that 102-84 win over the Blazers in which the Tar Heels weren't terribly happy to be trading baskets with them all night.
That wasn't a problem at all in this one.
North Carolina reeled off 15 straight points and, later, 19 in a row during the overwhelming run that gave it that 30-point cushion.
Among the high points: the Tar Heels hit 3-pointers on three straight possessions - two by McDonald, one by P.J. Hairston - to get things started. Freshman Brice Johnson had highlight-reel dunks on back-to-back trips down the court, including a pretty alley-oop from McDonald that made it 41-9 with about 2½ minutes left.
By then, the only thing in question was whether the mistake-prone Buccaneers could scrape together enough offense to get to 13 points - the previous mark for scoring futility in a half in this building.
When Rembert tossed up an air ball just before the halftime buzzer, that left it 42-12 at halftime - wiping N.C. State's dubious accomplishment in 2008 from the arena's record book.
Hunter Harris finished with 11 points for ETSU.