You may receive a “Service Unavailable” error when opening CRM in IE. Looking at the eventlog of the CRM server, it seems that Worker Process could not start correctly and show the following entry:
ISAPI Filter ‘C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\aspnet_filter.dll’ could not be loaded due to a configuration problem. The current configuration only supports loading images built for a AMD64 processor architecture. The data field contains the error number. To learn more about this issue, including how to troubleshooting this kind of processor architecture mismatch error, see http://go.microsoft.com/fwlink/?LinkId=29349.
This occurred on the CRM server for one of our customers after they installed a 32-bit application which also required a website in IIS called SolarWinds-Orion-NPM.
We are not sure if the installer reconfigured the IIS website, or the sysadmin did J
For IIS 6.0, it is not possible to run both 32-bit an 64-bit worker processes.
This is stated here on the MS website: http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/13f991a5-45eb-496c-8618-2179c3753bb0.mspx?mfr=true
On 64-bit Windows, the World Wide Web Publishing service does not support running 32-bit and 64-bit worker processes concurrently on the same server.
Anyway, switching the IIS website back to x64 mode solved our problem.
To do this for IIS6.0, run the following script in a Command Prompt:
// this will disable 32-bit mode on IIS
cscript.exe C:\inetpub\adminscripts\adsutil.vbs set W3SVC/AppPools/Enable32BitAppOnWin64 “false”
// this will register the .NET framework assemblies in 64-bit mode for IIS
C:\Windows\Microsoft.NET\Framework64\v2.0.50727> aspnet_regiis.exe –i
Your CRMAppPool should now start correctly