A signature update to Symantec's Endpoint Protection software has led to crashes of Windows XP. The problems with Endpoint Protection, a security package mainly used in the corporate environment, became noticeable by the frequent complaints from users and administrators to the company's support team and in Symantec's forums.

According to an information page, although Symantec has reproduced the problem, it is yet to identify the underlying cause. It has now, though, produced updated signatures to work around the problem. Measures to ensure that the updated signatures are downloaded and how to correct machines which are suffering the crashes are included in the document "SEP 12.1 Win XP Users Experiencing Blue Screen when running Proactive Threat Protection Definitions July 11th 2012 rev 11.".