Hillary Clinton repeatedly rejected the critical findings of the State Department Inspector General Sunday over her private email server on ABC's This Week, returning to her talking point that other secretaries of state used a personal account as well.

Yet, as host George Stephanopoulos pointed out to her, she was the only one to use it exclusively to conduct State Department business. Clinton appeared to grow flustered as she was questioned by the host, who worked in her husband's White House and is a donor to the Clinton Foundation.

"Do you accept now their conclusion that your exclusive use of a personal account was not allowed, that you broke State Department rules?" Stephanopoulos asked.

"I thought that the report actually made it clear that the practice I used was used by other secretaries, other high-ranking State Department officials—" Clinton started.

"No one else had exclusive use of a personal—" Stephanopoulos said.

"If I had to do it over again, I certainly wouldn't," Clinton said. "But I think that the rules were not clarified until after I had left, because it had been the practice of others. There was certainly reason to believe, which I did, that what I practiced was in keeping with others' practices."

The IG report concluded Clinton violated federal regulations designed to ensure integrity of classified information. MSNBC's Andrea Mitchell called the report "devastating" in that it contradicted Clinton's repeated claims that she complied with Federal Records Act regulations.

Stephanopoulos again pointed out Clinton exclusively used the private server. Colin Powell had a personal account, but he used that one sparingly.

With an edge in her voice, Clinton repeated the rules were not clarified until she left office.

"The first secretary of state to use a government email account was John Kerry, some months into his tenure," she said. "Those are the facts."

"So you don't accept the conclusions of the report, because they say you were unmindful of the rules," Stephanopoulos said.

"Everybody in the department knew that I was emailing from a personal address. Hundreds of people knew it," she said. "People around the government knew it, and that was what the practice had been, and that's what I did as well."

She added that she had not been asked to come in for an FBI interview over the matter.