Updated Sky is considering reversing an update to the software on its PVR boxes after it froze customers out of the programme guide and left them unable to record TV.

The update to Sky+ boxes, described as minor by the firm, was pushed last week over the air. Customers noticed the OS version number had changed when they were locked out last Tuesday.

Sky sent this statement:

We regularly upgrade the software in Sky+ boxes as part of routine maintenance and product enhancements. All software is tested rigorously against each hardware type of the box before being downloaded to customers' boxes.

We're investigating reports from a small number of Sky+ customers whose boxes are experiencing problems following a recent software update. Although our investigation is continuing, the problem appears to be isolated to a small minority of owners of a particular type of box, which in turn represents about 5 per cent of all Sky+ boxes. After reviewing call centre data and customer feedback, it appears that in the vast majority of cases the boxes concerned have had their hard disk drive changed for a non-standard component.

While our investigation continues, we are reviewing whether to reverse the software update to provide a short-term fix for the affected boxes. We'll consider longer-term steps once we've confirmed the scope of the problem.

Sky said it would carry out more testing today, and hopes to know whether to go ahead with the rollback by tonight.

Some people affected by the problems were told by call centre staff they would need a £65 engineer call-out to fix their box. Sky says customers shouldn't modify their set-top box, as it invalidates the warranty in the first year and makes it impossible to know for sure if software updates are bug-free later. ®

Update Thursday November 26

Sky indeed reversed the update last night and users report it has fixed the problem. Many Reg correspondents dispute Sky's version of events however, and say their unmodified Pace V2 was borked by the new software.