Running IIS in 64 Bit Mode

Internet Information Services (IIS) 6.0 supports both the 32-bit mode and the 64-bit mode (as long as your OS is 64-bit too!). However IIS 6.0 does not support running both modes at the same time.

• ASP.NET 1.1 runs only in 32-bit mode (but who's still using this?!)
• ASP.NET 2.0 (and up) runs in 32-bit mode or in 64-bit mode
• To run ASP.NET 1.1 and ASP.NET 2.0 web applications at the same time, you're stuck with IIS in 32-bit mode unfortunately

So here's how I setup IIS and ASP.Net to run in 64-bit mode:

1. Go to command prompt
2. Disable the 32-bit mode in IIS using the command line argument: cscript %SYSTEMDRIVE%\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 0
3. Install the 64-bit version of ASP.NET 2.0 on IIS using the command line argument: %SYSTEMROOT%\Microsoft.NET\Framework64\v2.0.50727\aspnet_regiis.exe -i
4. Make sure that the status of ASP.NET version 2.0.50727 is set to Allowed in the Web service extension list in IIS Manager. If you had been using ASP.Net in 32-bit mode before, you may need to Prohibit that version ASP.NET version 2.0.50727 (32 bit) first.