SharePoint 2007 on x64 - don't try to run 32-bit web apps!

We're slowly migrating services onto our new servers here at Black Marble. This morning we had one of those moments where significant amounts of wall kicking and teeth gnashing ensue.

Basically, we forgot that if you enable 32-bit .net support on IIS 6 it disables 64-bit support - you can't run 32 bit and 64 bit apps concurrently.

We spent a long time the other week getting our release version of SharePoint 2007 installed on one of our shiny Sun X2100 x64 servers. We expect the site to be quite large, so it made sense to run the x64 version of SharePoint.

Unfortunately, when 32-bit .Net apps were enabled by mistake, SharePpint and the other 64-bit web apps all stopped. Removing .Net 1.1 and running the aspnet_iisreg -i command from the x64 .Net 2 framework folder got us back up and running, but SharePoint refused to allow anyone to login.

Fortunately the Central Admin site was still working, so I had a rummage. It looked like SharePoint was no longer talking to our AD, so I went to the Application Management site, and went to the Authentication Providers option in the Application Security section.

In here you can edit the settings for each Web Application. I went through each of ours, and clicked on the 'Default' zone which is listed in the Web Application page.

I didn't need to change anything - simply hit the save button and SharePoint seemed to rewrite it's settings. Once this was done, our SharePoint started talking to people again.

Now, I don't expect you to hit the same crazy situation as we did, but it's nice to know that you can coax SharePoint back into life without restoring stuff from backup.