Exchange 2007 OWA Service Unavailable

Working where I do gives me the opportunity to work with the latest and greatest of technologies.  Exchange 2007 is, in my opinion, a huge improvement over 2003 in terms of speed.  However, it moved too far away from the familiar GUI (like vista did), and therefore some usability has suffered.

Because Exchange 2007 requires 64 bit processors (or at the very least an Intel processor that emulates 64 bit technology), Windows Server 2003 X64 is needed. This means that Exchange will use up as much RAM as it wants to (10 out of 12GB on our server). It also means that .net 1 and .net 1.1 DO NOT work well with it. There are scripts that enable IIS to support 32 bit processes, but who wants to muck up the works with 32 bit and 64 bit processes fighting for resources?

If you accidentally install the Windows update hotfix .net 1.1 on your exchange server (I know I did), then it will automatically convert your nice 64 bit Exchange server into a 32bit mixed-mode Exchange server. Which might not be bad, except for the fact that IIS doesn’t like to mix modes. And that takes me to the point of all this writing – IIS does NOT like 32bit and 64bit.

When the hotfix made Exchange go into mixed-mode, IIS freaked out and stopped supporting OWA (outlook web access). It hosted a site called “Service Unavailable”. Not very creative. And through lots of searching, I came upon a set of instructions that is quite easy and works every time I replicate the issue.

1.) Uninstall Hotfix 1.1. If you really need .net 1 support, you’ll have to look elsewhere. .net2 works just fine. It’ll ask you to reboot the server, which sucks.
2.) Uninstall .net 1.0. Read above if you really require .net 1 support.
3.) On your exchange server, run this from the command line: “%SYSTEMROOT%\Microsoft.NET\Framework64\v2.0.50727\aspnet_regiis.exe -i”
If you get an error indicating that IIS is in 32 bit mode, go to step 4, otherwise go to step 5.
4.) ONLY TYPE THIS IF YOU GOT AN ERROR. “cscript c:\inetpub\adminscripts\adsutil.vbs SET /w3svc/AppPools/Enable32BitAppOnWin64 False”
This will make it so you are in a pure 64Bit environment again. After a couple minutes, go to Step 3 and run that command again (it will pass this time).
5.) Restart IIS. Check your OWA or Exchange web access.

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