The security worries are sufficient to hold back companies from the pay-per-use hosting model of virtual servers, the IT research firm said.
The report - Forrester's Q3 Enterprise And SMB Hardware Survey, North America And Europe - said that 49% of survey respondents from enterprises and 51% from small and medium-size businesses (SMBs) cited security and privacy concerns as their top reason for not using cloud computing.
The survey of more than 2200 IT executives and technology decision-makers in Canada, France, Germany, the UK, and the US is billed as the firm's largest annual survey of emerging hardware trends for both enterprises and SMBs.
The general conclusion of the report and its survey was that cloud computing adoption is lagging.
The firms surveyed showed low interest in pay-per-use hosting of virtual servers, one of many types of cloud computing service offerings in the market.
The percentage of enterprise respondents using pay-per-use hosting of virtual servers is effectively unchanged from 2008, with three percent using or expanding usage, although the percentage interested and without specific plans has increased.
Just fiour percent of SMB respondents have already implemented pay-per-use hosting of virtual servers compared with 2two percent in 2008. Security, maturity, and concerns about costs led as the reasons why firms are not using servers hosted in the cloud.
Commenting on the figures, Tim Garmon, Forrester's senior analyst, said that 2009 has been a challenging year for hardware and infrastructure technology vendors, but users' 2010 investment plans indicate that this market is set for a rebound next year.
"Despite the hesitancy about cloud computing, virtualisation remains a top priority for hardware technology decision-makers, driven by their objectives of improving IT infrastructure manageability, total cost of ownership, business continuity, and, to a lesser extent, their increased focus on energy efficienc", he said.