The report was also expected to slam Comey for insubordination for going over the head of Attorney General Loretta Lynch in July 2016 when he announced that Clinton was careless but would not be prosecuted.
That probe includes a look at whether Trump himself tried to obstruct justice by firing Comey.
The U.S. Justice Department's Inspector General, Michael Horowitz, said in a letter that most of the process to sign off on the report and protect classified information it may contain "is now complete, and we anticipate releasing the report on June 14, 2018".
The agency was concerned that Clinton's use of a non-government computer server may have jeopardized classified information.
The president fired the FBI director in May 2017 with the White House claiming the dismissal was not about the Russian Federation investigation - but instead about the handling of the Clinton investigation - although Trump later told NBC the probe of Russia's role in the 2016 election was part of his reasoning.
The president's critics charge that he is trying to undercut the credibility of whatever ultimately results from the work of the office of Justice Department special counsel Robert Mueller.
The probe to which Trump is referring, covering the actions of then FBI Director James Comey and his deputy Andrew McCabe, among others, during the 2016 election, is not yet finalized - although details about its findings have begun to leak out.
Following that meeting, Lynch took the unusual step to say she would not recuse herself from the case, but would accept the FBI's recommendations in the probe.
Before Comey he did so, at least one senior Justice Department official informed the Federal Bureau of Investigation that publicizing the decision so close to the election would violate longstanding department policy.
The president tweeted earlier this week, questioning why the report hasn't yet been released.
The announcement comes after Senate Judiciary Committee Chairman Chuck Grassley again rescheduled a hearing, originally set for June 5, to go over the long awaited OIG investigation findings.
The report is expected to be critical of former FBI Director James Comey, a frequent target of Trump's Twitter rage.