Visual Studio 2010 Could not load file or assembly

Visual Studio build error: :
Error 15 Could not load file or assembly 'file:///C:\Documents and Settings\kumard\My Documents\Visual Studio 2010\Projects\LANSW.LMS\site\References\SwitchIT.DataAccess.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)


  • Right click on each *.dll file in Windows Explorer.
  • Uncheck “Read Only”.
  • Click “Unblock”.

If dll are stored in a network drive, move them locally and re-add your references.


Diganta Kumar has architected and developed software for more than a decade for a wide range of industries and development platforms and over the years has filled many roles including program manager, founder, developer, architect, team lead, mentor and project manager. Diganta is founder of two online IT businesses. He is a certified AWS Solutions Architect, certified Professional Scrum Master (PSM I), certified Professional Scrum Developer (PSD I) and ITIL Certified. He has presented at Microsoft Tech.Ed, Microsoft AppFest and Ark Group Intranet conference. He attends AWS Seattle Official Events, Seattle AWS Architects-Engineers, and AWS Cloud Commerce user groups. He likes to help, mentor and manage software development teams to improve and produce great software. He currently work as a Senior Technical Program Manager for Amazon Web Services.

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Posted in C#, Visual Studio
3 comments on “Visual Studio 2010 Could not load file or assembly
  1. Jens-Peter Giersch says:

    Are you sure that this resolves this issue?

    If I paste a path with “file:///” into the Windows Explorer, I get an error message stating the same: File not found.
    If I remove one of the slashes, everything works fine.
    But how do I tell VS2010 to use the correct path?

  2. I hate to admit it but you were right: Using a local location for the project files solved the problem.

    But I am a bit irritated: Isn’t it possible to put project files to a network drive? Not to helpful if I need to work on different machines…

  3. Andreas says:

    Thanks a lot , You’ve saved me lot’s of time , such an unpredictable solution was…

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