Eleanor Masson, 62, and Doreen Cruickshank, 55, denied stealing pounds 572,778 from the Aberdeen lawyers Storie, Cruden and Simpson.
The Crown had claimed the cash was embezzled between January 1982 and February 1991, while the women worked as legal cashiers with the firm.
But after only two witnesses had given evidence in the Aberdeen Sheriff Court trial - which began on 9 November and was initially expected to last several months - both accused were acquitted by Sheriff Kenneth Forbes, to gasps from the public benches.
The defence counsel in the case, Herbert Kerrigan QC and Edward Targowski QC, criticised the Crown for its "incompetence" during four years of compiling evidence.
The women were freed after the Crown was unable to continue its case because of difficulties in presenting evidence of bank statements under the Prisoners and Criminal Proceedings (Scotland) Act of 1993.
Sheriff Forbes rejected a Crown motion asking for the case to be deserted temporarily and for an extension until next April to allow the prosecution to change its method of presenting evidence.
Masson, of Burnieboozle Crescent, Aberdeen, and Cruickshank, of Gordon Court, Newmachar, near Aberdeen, showed no reaction as they left the dock, neither acknowledging the other. Lawyers for the Crown would not say if they would appeal, but added: "We are reviewing our position."
Melville Watson, a senior partner with Storie, Cruden and Simpson, later criticised the way the case collapsed. It is understood that the firm is pursuing a separate civil case against both women in the Court of Session in Edinburgh.Reuse content