%1 is not a valid Win32 application

%1 is not a valid Win32 application

   This happens when you switch the iis to run 32 bit web application on 64 bit os environment without uninstalling 64 bit runtime from IIS. %1 is not a valid Win32 application.

You need to install / uninstall asp.net framework version of aspnet_isapi.dll from appropriate folder before and after swithcing.

to install/uninstall run aspnet_regIIS.exe found at appropriate framework version

You should not assign 64 bit version of aspnet_isapi.exe found at C:\WINDOWS\microsoft.net\Framework64\v2.0.50727\aspnet_isapi.dll  
to handle .aspx or .axd or .asmx or .ashx if iis is running in 32 bit mode.

To handle those request assign 32 bit version of aspnet_isapi.dll found at C:\WINDOWS\microsoft.net\Framework\v2.0.50727\aspnet_isapi.dll to appropriate extensions, when iis is runnig in 32 bit mode.

Referance image.


It is an error to use a section registered as allowDefinition3dMachineToApplication beyond application level This error can be caused by a virtual directory not being configured as an application in IISString was not recognized as a valid BooleanString was not recognised as a valid datetimeApplication Pool and Worker processError The SSIS Runtime has failed to start the distributed transaction due to error 0x8004D01B The Transaction Manager is not available The DTC transaction failed to start This could occur because the MSDTC Service is not runningDo Not Disturb Registry [dnd]JQuery Form With ValidationBest Android ApplicationsConnection PoolingRestart IIS or recycle application poolAndroid install APK from computer application


My name is Satalaj, but people call me Sat. Here is my homepage: . I live in Pune, PN and work as a Software Engineer. I'm former MVP in ASP.net year 2010.
Disclaimer: Views or opinion expressed here are my personal research and it has nothing to do with my employer. You are free to use the code, ideas/hints in your projects. However, you should not copy and paste my original content to other web sites. Feel free to copy or extend the code.
If you want to fight with me, this website is not for you.

I'm Satalaj.