Environment specific issues that might stop a handler working

[burbowikds]

On another development machine, this handler works fine. It's a handler for test.js. My web config entry is identical to the one on the machine that the handler works for, as is the class inheriting IHttpHandler. It's all the same. But on my machine I get a 404 when trying to navigate to test.js.What I've Tried:

• Numerous iisreset commands. Resets without a problem, but doesn't resolve the issue.
• Many deployments, I've debugged the project that has the handler so that I'm sure it's running
• Accessing the test.js file at different locations.
• Relocated the entry from \[code\]<handlers>\[/code\] to \[code\]<httphandlers>\[/code\]

Please note: The ajax call to the file is also identical to the machine on which it all works. There's literally no difference in code (all latest from source control).Are there any environment specific issues I need to take into account when setting up handlers?