Solved: The web being updated was changed by an external process.

Today I had to troubleshoot SharePoint site provisioning code which misbehaved on a particular server. It is always fun if code works well on a dozen SharePoint farms and then fails on one farm.

The code is a really simple C# console app which reads an xml file and it then uses the taxonomy specified in the xml file to create a SP web.

As part of the provisioning, the code will activate a set of standard SharePoint features and then activate the custom developed features.

I used the application on many different SharePoint 2010 farms to provision over 30 sites but recently we ran the tool on a new farm and we suddenly started getting the following error when the code tries to activate the SharePoint Publishing Web feature:

Error: Provisioning did not succeed.  Details: Failed to initialize some site properties for Web at Url: 'http://demo/Contoso'  OriginalException: The web being updated was changed by an external process.

This is the original code – before I made changes:

Console.WriteLine("Creating a new web with title: " + webTitle);

site.AllowUnsafeUpdates = true;

SPWeb newweb = site.AllWebs.Add(webTitle, webTitle, webTitle, lcid, "STS#1", false, false);

site.AllowUnsafeUpdates = false;
Console.WriteLine("Web created. Ready to activate web features.");

if (newweb != null)
{
    ActivateWebFeatures(newweb);
}
Console.WriteLine("Web created successfully");

I discovered that the SPWeb newweb = site.AllWebs.Add( call actually returns the SPWeb object before all provisioning has been completed so the next time I try to update newweb I get the error “The web being updated was changed by an external process.”

In order to solve this I fetched the new updated instance of the SPWeb, so I added the following line of code: newweb = site.OpenWeb(webTitle);

The following code works well:

Console.WriteLine("Creating a new web with title: " + webTitle);

site.AllowUnsafeUpdates = true;

SPWeb newweb = site.AllWebs.Add(webTitle, webTitle, webTitle, lcid, "STS#1", false, false);

site.AllowUnsafeUpdates = false;

Console.WriteLine("Web created. Ready to activate web features.");

newweb = site.OpenWeb(webTitle);

if (newweb != null)
{
    ActivateWebFeatures(newweb);
}

Console.WriteLine("Web created successfully");