Could not load file or assembly 'Microsoft.Practices.EnterpriseLibrary.Common, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find t

Have you added Enterprise Library references to your project? The error says the version is 5.0 hence this is EntLib 5 which you can download from: https://docs.microsoft.com/en-us/previous-versions/msp-n-p/ff632023%28v%3dpandp.10%29 along with necessary documentation.

This application was inherited by me from programmer who has left the company.  
Changing any of it worries me as even minor changes have a large impact and it all seems to go wrong!

Its strange how this error does not always show.  It tends to show the first time the page is called then seems to work after that>?

Thank you.

here are my answers:


1. I have the source code on my laptop.
2. I am using VS 2015 pro.
3. I believe its a .NET 4.0 application.
4. When debugging on my laptop the error never occurs.

Have you made any change after the project was handed over to you? And is this the new server where you are trying to deploy or it was the same server where it was used to work earlier?


I was thinking, if you can try cleaning the contents of your deployment directory on Web Server and then redeploy a compiled solution?