The Office of the Attorney General (OAG), which last month decided to drop the case against one suspect, told AFP it had issued a discontinuation order in the case against a second man.
On November 2, 2020, convicted Islamic State sympathiser Kujtim Fejzulai killed four people in Vienna before being shot dead by police.
It was the first major attack in Austria in decades and the first blamed on a jihadist.
Two Swiss citizens who knew Fejzulai were arrested in the northeastern Swiss town of Winterthur just a day after the attack on suspicion they may have helped in its preparation.
The two, who were aged 18 and 24 at the time, were known to the police and were the targets of prior criminal cases over terror-linked offences.
The OAG acknowledged Thursday that no evidence had emerged that either man had participated in any way or had prior knowledge of the attack.
The older of the two men was meanwhile hit with a penalty in a separate case with no links to the Vienna file, the OAG said.
The penalty order, seen by Swiss media, indicated that he had been found guilty of violating Switzerland’s law banning Al-Qaeda, Islamic State and related organisations and of being in possession of “depictions of violence”.
According to the ATS news agency, an IS group video was found on his phone depicting people being executed and decapitated.
He was handed a six-month suspended prison sentence, a fine of 1,000 Swiss francs ($1,100, 950 euros), and three years’ probation, ATS said.
In light of this penalty, he would not be compensated for the 176 days he spent behind bars after his arrest following the Vienna attack, it added.
The OAG said a separate case was still pending against the younger of the two men, also on suspicion he breached the Swiss law banning Al-Qaeda, IS and related organisations, and over “allegations of depictions of violence”. “The presumption of innocence applies,” it stressed.