Could not load file or assembly 'Microsoft.ReportingServices.SharePoint.ObjectModel' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Question

Could not load file or assembly 'Microsoft.ReportingServices.SharePoint.ObjectModel' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
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This is a SQL Server 2012 Developer Edition of SSRS.
I am getting this error when navigating to http://servername/Reports. The reports site was working fine, until I installed a SQL 2014 Developer instance (including SSRS) on the same server.
I can still get to the http://servername/ReportServer site.
Neither of these are using Sharepoint.
Any help resolving this issue would be greatly appreciated.
Below is the stack trace.
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[FileLoadException: Could not load file or assembly 'Microsoft.ReportingServices.SharePoint.ObjectModel' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)] System.Reflection.Assembly._nLoad(AssemblyName
fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) +0 System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity,
StackCrawlMark& stackMark, Boolean forIntrospection) +416 System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +166 System.Reflection.Assembly.Load(String
assemblyString) +35 System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +190 [ConfigurationErrorsException: Could not load file or assembly 'Microsoft.ReportingServices.SharePoint.ObjectModel'
or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)] System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +1149
System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +323 System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +116 System.Web.Configuration.AssemblyInfo.get_AssemblyInternal() +36 System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection
compConfig) +212 System.Web.Compilation.WebDirectoryBatchCompiler..ctor(VirtualDirectory vdir) +174 System.Web.Compilation.BuildManager.BatchCompileWebDirectoryInternal(VirtualDirectory vdir, Boolean ignoreErrors) +57 System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath
virtualPath) +295 System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) +482 System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext
context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) +108 System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean
noAssert) +171 System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath(VirtualPath virtualPath, Type requiredBaseType, HttpContext context, Boolean allowCrossApp, Boolean noAssert) +52 System.Web.UI.PageHandlerFactory.GetHandlerHelper(HttpContext
context, String requestType, VirtualPath virtualPath, String physicalPath) +53 System.Web.HttpApplication.MapHttpHandler(HttpContext context, String requestType, VirtualPath path, String pathTranslated, Boolean useAppConfig) +519 System.Web.MapHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
+176 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +274
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Answer 1

Hi Glen，
"The located assembly's manifest definition does not match the assembly reference." is generally caused by the loaded assembly's version is different than the expected version application refers to.
In this case, it should be caused by:
While starting Report Manager, the backend process ReportingServiceService need to load assemblies it refers to
ReportingServiceService reads the compilation/assemblies element from web.config(under Report Manager virtual patch)
If the compilation/assemblies is not existing, ReportingServiceService loads all assemblies from Bin folder. It can be verified from call stack System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory(). ReportingServiceService
uses System.Reflection.Assembly.Load with the assemblies' name only to load assemblies.
The Assembly.Load tries to load from the specify assembly by name from GAC at first. If it is found from GAC, it won't be loaded from Bin folder any more.
Since Reporting Service SharePoint Integration mode is installed, a same assembly of 'Microsoft.ReportingServices.SharePoint.ObjectModel' with different version might be installed to the GAC. That causes the error "The located assembly's manifest definition
does not match the assembly reference."
For more information about the error message and the loading process, please see:
http://blogs.msdn.com/b/junfeng/archive/2004/03/25/95826.aspx
https://msdn.microsoft.com/en-us/library/yx7xezcf(v=vs.100).aspx
Thanks,
Jinchun Chen