Error opening Workflow Inventory due to bad solution deployment

Issue

When attempting to open the Workflow inventory, it will fail and populate a similar page as below:

Error Code

error CS1061: 'ASP._layouts_15_nintexworkflow_workflowgallery_aspx' does not contain a definition for 'ExportCsv' and no extension method 'ExportCsv' accepting a first argument of type 'ASP._layouts_15_nintexworkflow_workflowgallery_aspx' could be found (are you missing a using directive or an assembly reference?) at System.Web.Compilation.AssemblyBuilder.Compile() at System.Web.Compilation.BuildProvidersCompiler.PerformBuild() at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath) at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate

Resolution

In order to rectify this issue, it's recommended that you ensure the nintex solution deployment. Or you can perform a reinstallation of the latest nintex product and ensure the nintex solutions were properly deployed within your SharePoint farm, post installation.

The re-installation steps are listed here:

https://community.nintex.com/t5/How-To-s/How-to-retract-and-remove-Gac-files-for-Nintex-Workflow-and/ta-p/89703
 

Note: The above link is an example for 2013, however the retraction and redeployment scheme is the same for retraction:

nintexworkflow20XXenterprisefeatures.wsp 
nintexworfklow20XX.wsp 
nintexworkflow20XXcore.wsp 
nintexforms20XX.wsp
nintexforms20XXcore.wsp
nintexlivecore.wsp (NintexExternalPlatform)
Nintexcommon.wsp

and Deployment:

nintexcommon.wsp
nintexworkflow20XXcore.wsp
nintexworfklow20XX.wsp 
nintexworkflow20XXenterprisefeatures.wsp  
nintexforms20XXcore.wsp
nintexforms20XX.wsp
nintexlivecore.wsp  (NintexExternalPlatform)