Four counting machines broke down, Stratford's council leader said
The Conservatives have taken control of two councils in Warwickshire.
They took Rugby and North Warwickshire, which were previously under no overall control, gaining six and three seats respectively.
In Coventry, voters kept the council in Conservative control despite the Tories losing two seats to leave them with 28.
Warwick and Stratford district councils were forced to abandon their counts after new electronic counting machines broke down.
They were taking part in the pilot of a new counting system whereby ballot papers are fed into high-speed scanners.
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The aim is to improve security, efficiency and the cost-effectiveness of the election process.
Stratford District Council leader Les Topham said: "It is always the same with new technology - if it works it is brilliant, if it doesn't everything collapses.
"Four of the six machines have broken down so we are going to have to come back later."
After the voting continued by hand, the Tories increased their overall majority to 21 in Stratford.
In Coventry where a third of the seats were contested, the Conservatives won eight seats on the night.
Labour took 10, gaining four, and now have 23 in total on the council.