I need help with an odd problem. I have a collection of Umbraco 7 sites (various different versions) that run just fine on my local machine and on their production servers.

But on the staging server they all exhibit the same problem. Both front-end and backoffice requests will experience random 404 errors. Sometimes the 404 is for a physical file that I know exists: css, js files or an image.

But other times it's a request to an API endpoint. And upon refresh different requests will 404. Sometimes, rarely, there are no 404s. But each refresh is a gamble.

I have double-check the Umbraco configurations and the file permissions. On my test site I even went so far as to grant the local "Everyone" account full Modify permissions.

The App Pools are configured with .NET CLR version 4.0.30319 and Integrated pipeline mode.

When I run aspnet_regiis.exe -lv in the command line I get back:

aspnet_regiis.exe -lv
Microsoft (R) ASP.NET RegIIS version 4.0.30319.0
Administration utility to install and uninstall ASP.NET on the local machine.
Copyright (C) Microsoft Corporation. All rights reserved.
2.0.50727.0 C:\Windows\Microsoft.NET\Framework64\v2.0.50727\aspnet_isapi.dll
4.0.30319.0 C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll
4.0.30319.0 C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll

So it appears the .NET framework is installed and registered properly.

I'm at a loss here. This problem is making the staging sites unusable at this point.

Anyone seen this before or have any suggestions?

Thanks!