PC users to get advice on eliminating secret file

By CHRIS BARTON

Microsoft says it will provide advice to Windows PC users who are concerned about a hidden file that logs their visits to websites and defies most efforts to wipe it out.

The Herald has been told the file - index.dat - has been used for forensic evidence.

An employment consultant, who did not wish to be named, also said it was common practice in disciplinary cases involving inappropriate internet use for businesses to access the index.dat file and visit the sites listed.

Microsoft NZ technical marketing manager Terry Allen said there was nothing sinister about index.dat and its purpose was not to spy on PC users. Index.dat recorded stored web addresses because it was "an efficient process for managing the cache", allowing quick access to websites.

Asked why the file remained on PCs even after users had cleared the cache and why it appeared to grow over time, Mr Allen said that was how an index file worked. "When files are deleted, they aren't removed, but are overwritten over time - some [index.dat files] grow, some will not."

Mr Allen said he was awaiting further information from the United States to explain why some users had been able to read a history of web-based e-mail stored in their cache - even after it had been cleared.

He said index.dat could be removed using system tools without harming the PC but would be re-created each time users accessed the internet.

A number of readers have told the Herald they have known about the index.dat files for some time and have taken steps to ensure its removal - and their online privacy - by installing software such as Windows Washer, Spider and SurfSecret.

* For instructions on removing index.dat and old web-based e-mails, phone Microsoft Customer Services on (09) 357-5576.