SharePoint 2013 Site Collection | HTTP 404 error intermittently

Problem Description

Recently I came across a weird issue, a site collection in the SharePoint farm was giving HTTP 404 intermittently. My initial thought was maybe the whole web application had the issue but didn’t see this happening with any other site collections on the same web application. And I got this error only 1 out of 10 times. But another user seemed to have got it from the first try itself. It really baffled me for couple of hours. So I did an IIS reset and even restarted the SharePoint timer service on the SharePoint web front ends. That didn’t seem to help either.

Resolution

At some point, I realized that this was a site collection specific issue. This site collection had its own dedicated database. I had to detach and attach the content database of this site collection from the web application using Powershell (read dismount and mount)to resolve this issue.

Few weeks back I had done a detach/attach of the same content database from Central Administration. I think performing dismount and mount from Central Administration console led to this behavior. I still find this weird though.

P.S.: Please make a note of the Content DB name before you start this operation

Dismount-SPContentDatabase "<ContentDBName>"

Mount-SPContentDatabase "< ContentDBName >" -DatabaseServer "<DBServerNAme>" -WebApplication http://SiteName