After the decision was announced, prosecutors said they plan to re-try the case.
The jury deliberated a total of about 52 hours over about five days after a trial that moved at a brisk pace for the first six days.
After numerous pre-trial hearings before O'Neill, most of which Cosby lost, trial was set for June 5.
The comedian is accused of sexually assaulting Andrea Constand in 2004. His reputation may still be in tatters, but for now he'll be a free man.
The man once best known to USA audiences as "America's dad" faces similar accusations from dozens of women, though only Constand's allegations have resulted in criminal charges.
Cosby did not testify on his own behalf during the trial, despite rumors that circulated late last week.
On Friday morning, jurors came back with more questions.
Constand, the woman at the center of the charges filed against Cosby, spent almost eight hours over two days on the witness stand.
The sequestered jurors had deliberated about 30 hours before telling Judge Steven O'Neill earlier Thursday that they couldn't reach a unanimous decision on any of the counts against the 79-year-old comedian.
He called Constand a liar and said inconsistencies in her statements to police should cause reasonable doubt. "And I felt Mr. Cosby's hand groping my breasts under my shirt".
Cosby was charged with three counts of aggravated indecent assault. That was over in 2005. McMonagle has said Wyatt was not speaking at his direction. "We're here because of them".
The case has already helped demolish his image as America's Dad, cultivated during his eight-year run as kindly Dr. Cliff Huxtable on the top-rated "The Cosby Show" in the 1980s and '90s.
Prosecutors said they would retry Cosby, who remains charged with three counts of aggravated indecent assault. Officials cited newly-publicized testimony from a 2005 deposition in a civil case filed by Constand. Specifically, they wanted to hear the portion about Quaaludes and Cosby's knowledge of, use and access to them.
Cosby lead defense attorney Brian McMonagle then motioned for a mistrial, which O'Neill promptly granted.
Andrea Constand, right, returns to the courtroom at the Montgomery County Courthouse during Bill Cosby's sexual assault trial Thursday, June 15, 2017, in Norristown, Pa. Cosby is accused of drugging and sexually assaulting Constand at his home outside Philadelphia in 2004.
Judge Steven O'Neill refused, saying there's no precedent to halt the jury's work.
That woman testified first in the criminal trial. He said Cosby had been unfaithful to his wife but he didn't commit a crime.
Constand's mother was another main witness for the prosecution.
Cosby's defense team didn't dispute much of the facts, but instead claimed the encounter was consensual. Cosby has denied every accusation and said his encounter with Constand was consensual.
Steele told jurors the case was straightforward, resting on three pillars: One, that Cosby drugged Constand. He also described Cosby as an imperfect philanderer - not a sexual predator. "And she deserved better".
Bill Cosby's lawyer has repeatedly demanded a mistrial as the talks wore on without a verdict, but the judge said there was no precedent to send the jury home.
"This is pretty fundamental: lack of consent", Steele said.
Manchester United's latest signing Victor Lindelof arrives at Old Trafford with a reputation for taking a mean free-kick. Mourinho has set his sights on signing Real Madrid striker Alvaro Morata to bolster his strike force for the new season.
However, graphics and game choice might be playing a role in how many people actually want the console to begin with. Unless you've been living under a rock these last seven days, you'll have no doubt heard about the Xbox One X.
The cause of the blaze is under investigation, but a tenants' group had complained for years about the risk of a fire. Residents in other blocks with the same exterior cladding as Grenfell Tower were concerned, he wrote .
He said he "Army-crawled" his way to taller grass and tried to reach the dugout, but bullets were hitting the dugout as well. He was airlifted to MedStar Washington Hospital Center Wednesday and is in critical condition recovering from surgery.
It was announced in April that the deadline for parties there to reach a deal would be pushed out until June 29th. On Brexit , Ms Foster said her party wanted to see "a sensible Brexit and one that works for everybody".
Reports said Trump approached Coats and Rogers to get their help in derailing the Russian Federation investigation. Comey told Congress last week that he believed he was sacked "because of the Russian Federation investigation".
North Korea is said to possess such missiles with a roughly 100km range for use against targets including aircraft carriers. The short-range missiles flew some 200 kilometres before dropping into the East Sea, a Defence Ministry spokesman said.
Halep will meet Carla Suarez Navarro in the next round after the Spaniard battled past Russia's Elena Vesnina 6-4 6-4. Over on Court Suzanne Lenglen, 2015 champion Stan Wawrinka takes on Italian Fabio Fognini , who is seeded 28th.
Asked Thursday whether the death toll might exceed 100, Cundy said "I'd like to hope that it isn't going to be triple figures". Opposition Labour leader Jeremy Corbyn has called for houses in the area to be "requisitioned" for survivors.
People react near a tower block severely damaged by a serious fire , in north Kensington , West London , Britain June 14, 2017. Other members of her Conservative Party urged her to show concern for the dozens of victims and survivors of the blaze.
Rosenstein says he's seen no good cause to fire counsel
Feinstein has said the Judiciary Committee should investigate, but had asked Grassley to keep the investigations separate. Indeed it was a recommendation from Mr Rosenstein last month that led Mr Trump to sack then-FBI director James Comey .
Theresa May pledges £5M for Grenfell Tower victims
Detective Chief Inspector Matt Bonner from the homicide and major crime command has been appointed to lead the investigation. Commander Stuart Cundy said they had been able to remove the remains of only 12 victims from the building.
US Open 2017: Rory McIlroy misses cut for second year
The bigger issue was he took 31 putts compared to 27 on Thursday, the one area of his game he did call out after the round. McIlroy said he would be hitting the practice ground this weekend. "There is ample room to hit it, so it's really fair".
London tower block inferno: What we know
The residential tower was built in 1974 and had been extensively refurbished in works that were completed previous year . Detective Superintendent Fiona McCormack said the lingering threat had also hampered the process of recovering bodies.
Play ball! GOP, Dems to battle as 1: Team Scalise
More than 20,000 tickets had been sold as of Thursday afternoon, organizers said, which is enough to fill half the stadium. Even President Donald Trump , who rode to the White House on a road of division, rightly called for unity.
Trump thrusts US, Cuba back toward hostile relations
Marco Rubio, who claims credit for writing the Trump policy along with a fellow Cuban-American and Florida Republican, Rep. Once implemented Trump's policy is expected to curtail U.S.travel by creating a maze of rules for Americans to obey.
Belmont Stakes: Watch Tapwrit run to victory
And Tapwrit's victory over the gritty Irish War Cry was a popular one with the crowd of 57,729. "I'm very happy right now". Tapwrit , which had 5-1 odds to win, started in the second post . "I always had a lot of faith in him", Ortiz said.
India and Pakistan face off in dream cricket final
Pakistan bowling coach Azhar Mahmood said Amir was fit but did not indicate whether the speedster would play on Sunday. While this is Pakistan's first Champions Trophy finals, it's fourth for team India.
IOS 11 Will Stop App Developers Abusing Location Permissions
At WWDC, Apple reported that they've paid out $70 billion to developers, with 30% of that ($21 billion!) in the previous year . That's a huge spike, and surprising to me because it didn't seem like my friends and I were spending more on apps past year .