Symantec bug takes down PCs

Users get blue screen of death.

Hundreds of Windows computers were rendered unusable last week thanks to a bug in a Symantec anti-virus software update. 

Windows XP users were repeatedly treated to the so-called blue screen of death late on July 11 as a result of the update to Symantec’s Endpoint Protection 12.1 and Norton software.

Symantec blamed the bug on software compatibility issues.

“The root cause of the issue was an incompatibility due to a three way interaction between some third party software that implements a file system driver using kernel stack based file objects – typical of encryption drivers, the SONAR signature and the Windows XP Cache manager, “ it said on its website.

“The SONAR signature update caused new file operations that create the conflict and led to the system crash.”

It admitted it had neglected to catch the bug in its initial testing.

“The compatibility testing part of the quality assurance process for SONAR signatures missed catching this compatibility issue. It is this part of our process that we will be improving to avoid future issues,” it said. 

“We are currently restructuring our testing process to improve compatibility testing and will not be releasing new SONAR signatures until this new process is in place.”

The issue was resolved just over five hours later, though Symantec said customers needed to manually remove the software to fix their PC.

Symantec estimates around 300 business customers and 60 consumer customers have been affected so far.

Symantec Australia declined to comment on how many Australian users were affected.

Customers affected by the bug can visit