Investigators have dismissed allegations of a “dirty tricks” campaign against the Scottish Labour leader during the Holyrood election campaign.
The Information Commissioner’s Office (ICO) told The Press and Journal that no further action would be taken over the leak of Kezia Dugdale’s bid for work experience at the SNP.
But a Scottish party leader called on those responsible to apologise for their smear attempt on Ms Dugdale.
Details of her application to the SNP when she was an Aberdeen law student emerged in April, as the Scottish Parliament election campaign entered its final weeks.
Ms Dugdale said at the time she feared it was the start of “dirty tricks” campaigning by the Nationalists.
She added she had “absolutely no recollection” of making such an application.
Her detractors claimed it exposed her as a career politician and further undermined her stance on Scottish independence.
A senior SNP source was quoted at the time as saying “no one can take her seriously now”.
But party leaders, including the SNP’s Nicola Sturgeon, said it was unfair to judge young people in their pursuit of work experience.
An ICO spokeswoman said: “Our inquiries are complete and we are satisfied there is no further action for us to take.”
During the campaign it emerged that Ms Dugdale wrote to Moray MSP Richard Lochhead, who later became the rural affairs secretary, asking for a work placement in 2003.
When challenged by The Press and Journal in April, Mr Lochhead said he was not responsible for any leak, adding “it’s not my style”.
Scottish Liberal Democrats leader Willie Rennie, who made the complaint to the ICO, said: “This ruling does not change the fact that details of Kezia’s youthful job application were leaked in an attempt to embarrass her.
“This was a sorry episode and those responsible should do the right thing and apologise to her.”
Under the Data Protection Act, there is a legal obligation on organisations to keep personal information private and not to hold it longer than required.
Ms Dugdale and the SNP declined to comment.