The company experienced difficulties after restructuring plans failed to live up to expectations and attempts to revive consumer interest in core brands were unsuccessful.
Now 149 jobs will be lost as the ailing confectionery business waits for a buyer.
Millar McCowan produce Wham bars, Highland Toffee and various hard sweets such as bonbons and mints. The independent company lists major retailers such as Tesco, ASDA and Morrisons among its customers.
Millar McCowan has two factories in Scotland employing 157 workers and recorded sales of around £8m (€11.9) per year.
It was formed last year after the businesses and assets of two confectionery companies - Millar and Sons and McCowan's - were acquired out of receivership.
McCowan's, founded in Stenhousemuir, Scotland in the 1920s, was previously owned by Swiss food conglomerate Nestlé and then Dutch confectioner Phideas, before returning to Scottish ownership with the merger.
Highland Toffee was produced by the company for more than 80 years while the core Wham brand has been available since the 1980s and is particularly popular with children.
The company which was to become the second part of the Millar McCowan partnership, Millar and Sons, went into receivership in May last year, blaming aggressive supermarket pricing and high costs for raw materials.