More than seven in 10 used but functional hard discs bought on eBay and examined for the study by Berlin-based hard disc utilities company O&O software still had valuable and easily recoverable data on them.
This year's figure of 71.5% represents a small improvement on a similar survey last year, when 88% of discs were found to contain data: but disc sizes have increased substantially this year. Researchers reconstructed more than 3.3 million files and found 50 e-mail mailboxes, complete with the previous users' e-mails.
The report said, "The results in 2004 were alarming. In 2005, the results show a small improvement. However, even when the percentage of recoverable data on the tested hard discs has fallen, the 'quality' of recovered data has improved dramatically.
"One of most dramatic findings of this year's study was a hard disc apparently from a federal governmental body in Germany. Along with reports and minutes of meetings, this disc contained correspondence concerning details of a running external investigation.
"Also found was a hard disc once belonging to a prominent German bank that contained information regarding the credit ratings of other banks."