About 160 jobs are under threat at a printing firm's two bases in Derby.
The Unite union said staff were sent home from Bemrose Booth at Pride Park and Wyvern Business Park on Monday.
A spokesperson for the firm confirmed it had filed a notice of intent at the High Court to appoint an administrator.
He said the firm had been losing money over the past few years because of the economic climate and competition within the printing sector.
Jerry Marsden, who has worked for the company for seven years, said workers had been unaware of the problems when they turned up for work on Monday but added: "Then we found out they're ceasing business at Derby.
"Everyone's thoroughly fed up, angry and dejected. We've all got bills to pay."
Kathy Brooks, regional officer for Unite, said: "The workers are at rock bottom.
"We will do everything we can to assist our members in finding alternative employment."