Could not load file or assembly 'DevExpress.Web.Mvc5.v15.1

[FrediG]

I've upgraded my On-Prem FNMS from 2023R1 to 2024R1. When I try to access the FNMS system I get the following error:

Server Error in '/Suite' Application.

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Configuration Error

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: Could not load file or assembly 'DevExpress.Web.Mvc5.v15.1, Version=15.1.15.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a' or one of its dependencies. The system cannot find the file specified.

Source Error:

Line 79: 				<add assembly="DevExpress.Utils.v23.1, Version=23.1.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" />
Line 80: 				<add assembly="DevExpress.Web.ASPxTreeList.v23.1, Version=23.1.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" />
Line 81: 				<add assembly="DevExpress.Web.Mvc5.v15.1, Version=15.1.15.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" />Line 82: 				<add assembly="DevExpress.Web.v23.1, Version=23.1.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" />
Line 83: 				<add assembly="DevExpress.RichEdit.v23.1.Core, Version=23.1.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" />

Source File: C:\Program Files (x86)\Flexera Software\FlexNet Manager Platform\WebUI\web.config    Line: 81

Assembly Load Trace: The following information can be helpful to determine why the assembly 'DevExpress.Web.Mvc5.v15.1, Version=15.1.15.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a' could not be loaded.

[Flex-Jeremy · Accepted solution]

You will need to update the Web.config file manually with the correct version of the DevExpress.Web dll that FNMS 2024 R1 uses. Use the following PowerShell command to identify the version of the DLL that is installed. You may need to adjust the file path that is specified. 

([system.reflection.assembly]::loadfile("C:/Program Files (x86)/Flexera Software/FlexNet Manager Platform/WebUI/bin/DevExpress.Web.Mvc5.v23.1.DLL")).FullName

You can then modify the Web.config file with the appropriate version information for the DevExpress.Web DLL.

After making this change you will need to perform an IIS reset before accessing the FNMS Web UI. 
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This error is cause because a Flexera process was running when the upgrade was performed. 

[FrediG]

Hi Jeremy, thanks, I applied what you suggested, and I am able to access the frontend. Only problem is that I get red bar errors on some of the pages which I try to access, but can still see the data.

[FrediG]

I got it sorted now. After I implemented the solution above I went and stop all tasks and the BatchProcess services and rerun the config.ps1 script. This resolve the red bar issue.

Thanks again Jeremy for the assistance.