It had been claimed by a Chinese rights group that Vole was omitting websites from its Bing search engine results for users outside China to appease Chinese mandarins.
GreatFire.org, a China-based freedom of speech advocacy group, said in a statement Bing was filtering out both English and Chinese language search results for terms such as "Dalai Lama", the exiled Tibetan spiritual leader whom Beijing brands as a violence-seeking separatist.
However Microsoft blamed the problem on a systems fault which had removed some search results for users outside China.
Stefan Weitz, senior director for Bing, crooned in a statement emailed to Reuters that an error in its system triggered an incorrect results removal notification for some searches noted in the report but the results themselves are and were unaltered outside of China.
He did not say if the error had been fixed. Reuters noted that Microsoft sent a shortened version of the statement to China-based media organisations which omitted all reference to GreatFire.org and did not address the claims.
Bing omitted several websites that showed up on the search engine of rival Google when they searched for "Dalai Lama" in Chinese from Singapore. The English-language search results on both engines were similar.
This is the second time that Vole has been slammed for helping the Chinese censor things. It was criticized for censoring the Chinese version of Skype, which it ran jointly with Hong Kong-based TOM Group. In November, Microsoft said it had formed a new joint venture with Guangming Founder, and advocacy group GreatFire.org said Skype in China was no longer being censored.