Why .NET Framework process uses 100% CPU

At the time I didn't know that it was a .NET Framework process, but after some research, I found out its whole story.

MSCORSVW.EXE is a process used by the .NET Framework to precompile .NET assemblies in the background. It tends to run most on two occasions:

• Right after you've installed the .NET Framework redistributable, when it needs to compile the highest-priority assemblies, and
• After an application that uses the .NET Framework has been installed and needs to have its assemblies compiled.

(Note: The process will not run on multiple cores or processors, as a deference to the user's needs. For instance, if it's pegging at full usage on a two-core machine, it will be listed as using up 50% of available CPU.)

The process usually only runs as low priority, meaning that if other processes are running, it should cede CPU usage to them. When it does this, it will work through a queue of assemblies that need to be compiled, so it's not unusual to see...

Digg This!     StumbleUpon     Del.icio.us

RELATED CONTENT Microsoft Systems and Network Troubleshooting DNS troubleshooting best practices Troubleshooting tops Windows admins' most tedious tasks Troubleshooting Windows application crashes or hangs Troubleshooting poor Windows logon performance in Active Directory environments Immediate steps for Windows disaster recovery Quick hits: Troubleshooting service account failure, batch job execution Case Study: Troubleshooting Windows service dependency failures Troubleshooting common Windows service failures How can I boot to a floppy and receive a command prompt without being directed to the system drive? RRAS utility in Windows Server 2003 traces network problems Windows Server Monitoring and Management How Windows Server 2008 R2 stands up to security checks BitLocker in R2 provides data protection for semi-protected servers Perfmon made easy with PAL utility Converting Citrix XenServer source machines to Hyper-V format Balancing Windows security with reasonable password policies Windows AppLocker in R2: Turning conventional security wisdom on its head Top 10 things you don't know about Windows Server 2008 R2 BranchCache makes branch offices feel like home When to use VM backups versus snapshots in Hyper-V Installing Server Core for Windows 2008 the easy way

RELATED RESOURCES 2020software.com, trial software downloads for accounting software, ERP software, CRM software and business software systems Search Bitpipe.com for the latest white papers and business webcasts Whatis.com, the online computer dictionary

it running for a few minutes on end if there's a lot of work to be done.

But if the process is running at 100% and refuses to cede to other processes, it is either compiling high priority assemblies, which need to be completed as soon as possible, or else there's something wrong with the .NET installation.

One way to get the process to crank through all of its pending work at once is to issue the command ngen.exe executequeueditems from the .NET executables directory. If this doesn't work—i.e., if the process remains at 100% for minutes on end—the .NET installation may be damaged and should be removed and reinstalled. However, this doesn't happen very often; it's often just that there's a large queue of work that's suddenly been set up.

About the author: Serdar Yegulalp is editor of the Windows Power Users Newsletter, which is devoted to hints, tips, tricks, news and goodies for Windows NT, Windows 2000 and Windows XP users and administrators. He has more than 10 years of Windows experience under his belt, and contributes regularly to SearchWinComputing.com and SearchSQLServer.com.