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Unable to access VSA Login page with error message "Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'." - Connect IT Community | Kaseya
<main> <article class="userContent"> <h3 data-id="problem"><strong>Problem</strong></h3> <p>Unable to access VSA Login page with error message:</p> <p> </p> <p>Server Error in '/vsaPres' Application.</p> <p>Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.</p> <p> </p> <p><img src="/attachments/token/DxP1Y25BAgIb07PwKHCC0ZHjW/?name=2015-06-06_1252.png" alt="2015-06-06_1252.png" class="embedImage-img importedEmbed-img"></img></p> <p><strong>Cause</strong></p> <p> </p> <p>The server is running an older .NET version. ASP.NET is looking for a file that does not exist. The reason being the file is part of the newer .NET version - .NET 4.5.</p> <h3 data-id="solution"><strong>Solution</strong></h3> <p>1) To run Windows Update and install all Pending Updates</p> <p>OR</p> <p>2) Install .NET 4.5 manually using the following link: <a href="/home/leaving?allowTrusted=1&target=https%3A%2F%2Fwww.microsoft.com%2Fen-gb%2Fdownload%2Fdetails.aspx%3Fid%3D30653">https://www.microsoft.com/en-gb/download/details.aspx?id=30653</a><br><br></p> <h3 data-id="applies-to">Applies to</h3> <p>Kaseya VSA - All versions</p> </article> </main>