Is your asp.net web app (deployed on IIS)  using framework 4.5 ? How do you tell?

Just looking at the framework column (for the specific app pool) in IIS will show you 4.0 (since 4.5 is just a set of extensions on top of 4.0 and NOT a new framework). 
Read this for successfully compiling against 4.5 framework and successfully creating an IIS app pool.
The answer is – You cannot tell by looking anywhere that your app pool is correctly using 4.5. 
Even if you have the 4.5 runtime installed, there is nothing that show you that your app pool is using it!

Quick Workaround

To ensure that your app pool IS using the correct framework, you have to EXPLICITLY assign the framework to the app pool (as shown below)
appcmd set apppool /apppool.name: [App Pool Name] /managedRuntimeVersion:v4.5

Appcmd is located in %windir%\System32\inetsrv.

That’s it – that should ensure (no guess work) that the 4.5 framework is being used by the app pool. If your app pool still fails to start (due to some part of your project not being correctly upgraded to run on 4.5), the next place to look is the IIS logs.

IIS 7.5 Log File Location

Anuj holds professional certifications in Google Cloud, AWS as well as certifications in Docker and App Performance Tools such as New Relic. He specializes in Cloud Security, Data Encryption and Container Technologies.

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Anuj Varma – who has written posts on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

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