Cannot create unknown type http://schemas.uipath.com/workflow/activities InvokeWorkflowFile - Solution Steps

Issue details:
Error message: Cannot create unknown type ‘{http://schemas.uipath.com/workflow/activities}InvokeWorkflowFile’.

Reason of issue:

  1. The issue is because packages are not downloaded in the Robot machine and Robot is looking for the missing packages in Orchestrator, MyGet & Nuget location and they are not available in either of the locations. (if for the first time the process is being executed)
    Or,
  2. The currently installed packages are corrupt due to the unknown reason for example - abruptly Robot crash or server crash (the process was working fine and it stopped suddenly or after an upgrade)

Quick Solution Approach (considering 2nd as the reason for the issue )

  • Open %userprofile% in your affected Robot system

  • Navigate to “.nuget” folder.
    image

  • Take a backup of the “packages” folder to a different location.

  • Delete the current folder in .nuget location.
    This would delete all the packages thus allowing to Robot to download the packages again when a process is executed.

  • Now download & execute the process from the Robot tray / from Orchestrator.
    The process will download again with all the required dependencies.

This should solve the issue.
If not, please follow the below steps of moving the project dependencies of manually moving packages (the ones listed in the PROJECT.JSON file) to Orchestrator NuGet package location.
On execution, Robot would download from Orchestrator configured package location.

Approach 2nd: (considering 1st as the reason for the issue)
Please find the fix in the below article.
https://forum.uipath.com/t/cannot-create-unknown-type-v2018-2-3-onwards-troubleshooting-steps/72941

You need to identify all the missing package version from the Project,json file of the developed project or from the eventviewer logs.
Copy the nupkg file from Studio machine to the Orchestrator location to resolve the dependency issue.
Alternate, White list the IP address. (All details in the above link)

Moving the identified packages from Studio machine machine to Orchestrator server will fix the issue.