We are having problems in one of our sites. The sites occasionally goes down with a NullReferenece exception when user controls are being loaded. The strange thing is that if we change some code, or try to fix suspects in the user control mentioned in the exeption message, the same error will happen, but then maybe with a different user control referred to in the exception message. IISReset will not fix the problem, however if we stop the site in IISmanager, then just start it again, the site comes back up with no problem. Then it may work for severeal hours before it suddenly stops working again. Anyone have an idea of what to look after? Things to test?
System is Windows server Enterprice SP2 64bit. Other sites are running just fine on the same server.. Hope someone can help me on this one
best regards Fredrik
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 07.04.2011 00:00:00
Event time (UTC): 06.04.2011 22:00:00
Event ID: 44976d54f104459fa6b747a9cd0aa357
Event sequence: 6
Event occurrence: 1
Event detail code: 0
Application domain: /LM/W3SVC/2/ROOT-1-129466007785078891
Trust level: Full
Application Virtual Path: /
Application Path: C:\xxxxxxxxxx\
Machine name: xxxxx
Process ID: 4528
Process name: w3wp.exe
Account name: xxx
Exception type: NullReferenceException
Exception message: Object reference not set to an instance of an object.
Request URL: xxxxxxxxxxx/default.aspx?id=3&epslanguage=no
Request path: /default.aspx
User host address: xx.xx.xx.xx
Is authenticated: False
Thread account name: xxxxxxxxx
Thread ID: 10
Thread account name: xxxxxx
Is impersonating: False
Stack trace: at EPiServer.Templates.Public.Units.Static.Header.OnLoad(EventArgs e)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
After further investigation, we found that a 3 party dynamic content dll had a security setting: this file came from another computer and might be blocked to help protect this computer. OK, unblocked this dll, and now at least the sites comes up normally after an iisreset. Hoping this fix the occasionally site crashes as well!
Ah, the old assembly blocking demon... Blogged about it here: http://world.episerver.com/Blogs/Magnus-Paulsson/Dates/2011/2/Todays-gotcha-Windows-7-assembly-blocking/