We wanted to let you know that an update was released earlier today that will improve Internet Explorer’s reliability for users running the Windows 7 Beta. The update is now available via Windows Update, and can also be downloaded via Microsoft Update.
In this post we’ll discuss how we used the information that we’re receiving from Windows 7 Beta customers to determine the reliability fixes to include in this update.
We use the term “reliability” to broadly encompass all types of stability problems including crashes, hangs, memory leaks, etc. When we measure reliability we rely primarily on instrumentation built into Internet Explorer 8 and Windows 7. For example, the Customer Experience Improvement Program enables us to better understand how customers use our products, and Windows Error Reporting provides detailed information about the problems customers encounter. Shortly after the Windows 7 Beta became publically available these systems began to send information back to Microsoft.
After a week of monitoring this feedback we felt that we had reached a representative sampling of our customers. We found that approximately 10% of customers who had downloaded the Windows 7 Beta had experienced some type of reliability problem in IE8. We also found that a small number of users were experiencing crashes on a more regular basis and that about 1.5% of all Internet Explorer sessions had encountered a crash. This is relatively good for a pre-release version of Internet Explorer running on a beta operating system. We were also pleased to see that the new IE8 Crash Recovery feature was successfully helping customers recover from these crash situations 94% of the time.
One of the approaches that we use to analyze this data is called a failure curve. A failure curve is essentially a bar chart where each bar represents a unique failure (crash, hang, etc.). The height of the bar represents the number of occurrences in the last 30 days. Below you can see the failure curve for Internet Explorer 8 on Windows 7 Beta. The color indicates whether the failure is caused by Internet Explorer or a 3rd party toolbar or extension running inside of Internet Explorer.
As you can see about 40% of our reliability problems were caused by Internet Explorer and about 60% by 3rd party components. Another interesting point is that 17 unique issues account for 50% of all reported reliability problems. Because users generally have lots of toolbars and extensions installed, it’s common to see this many 3rd party components at the top of our failure curve.
Once we had the failure curve set up we began investigating each unique issue starting from the top of the curve. We started to understand the technical details of our own issues and developed fixes for them. For 3rd party problems we worked closely with our partners to address each issue either through an update to the 3rd party code, by working around the problem inside of the Internet Explorer code base, or as a last resort by preventing the 3rd party component from loading.
Most of the issues that we discovered through the Beta are fixed in the Release Candidate 1 which is now available for Windows Vista and Windows XP. We also wanted some of these fixes to reach our Windows 7 Beta users now. We decided to piggyback onto this first update for the Windows 7 Beta.
This update will address many of the top crashes and hangs from the Windows 7 Beta, which includes those caused by Internet Explorer as well as 3rd party components like Adobe Flash, Adobe Acrobat, and several others. We have also included fixes to enable printing PDF files and an architectural change which improves cookie management. This update does not contain other changes introduced between the Windows 7 Beta and Internet Explorer 8 Release Candidate 1.
We encourage everyone to download this update and provide feedback. Your feedback was the driving force behind many of the decisions we made and we appreciate your continued participation during the Windows 7 Beta cycle.
Herman Ng Program Manager