Unattended Robot Error “Could not load file or assembly 'UiPath.UiAutomation.Activities'” even after uploading package to Orchestrator Libraries

Help Orchestrator
1

I am encountering an issue when executing my automation through Orchestrator in unattended mode. The process runs successfully in UiPath Studio, but fails in Orchestrator with the following error:

`Could not load file or assembly 'UiPath.UiAutomation.Activities, Version=25.10.16.0,

Environment Details:

UiPath Studio version: 2025.10.x
Orchestrator: Automation Cloud (Modern Folders)
Execution type: Unattended
The process runs fine locally in Studio and Assistant
The issue occurs only when triggered from Orchestrator

Troubleshooting Steps Taken:

  1. Uploaded UiPath.UiAutomation.Activities.25.10.16.nupkg manually under Orchestrator → Tenant → Libraries → Upload.
  2. Verified that the library appears successfully in Orchestrator.
  3. Feed settings configured to “Both host and tenant feeds”, with deployment set to Internal.
  4. Cleared cached package folders:
%ProgramData%\UiPath\Packages  
%UserProfile%\.nuget\packages

Both folders were empty before clearing.
5. Attempted to restart the UiPath Robot service, but could not locate UiPathRobotSvc or UiPath.Service in the Windows Services list. Only UiPath Assistant-related processes are visible in Task Manager.
6. Machine credentials are correctly configured; no credential-related errors appear.
7. Despite these steps, the same assembly load error persists.

Current Behavior:

The job fails with:

System.IO.FileNotFoundException: Could not load file or assembly 'UiPath.UiAutomation.Activities, Version=25.10.16.0'

It appears that the unattended robot cannot locate or download the UiAutomation activity package, even though it exists in the Orchestrator library feed.

2

Hi @Iqra_Javed

Please refer below post and see if this helps

3

is your robot running in user mode ?

check which service is running,
UiPath.Service.Host.exe
or
UiPath.Service.UserHost.exe

4

UiPath.Service.UserHost.exe

5

so its a user service that is running.. that explains why your robot is running normally when you trigger from studio and from assistant( as it runs under already open user session - just like an attended robot. the nuget repository could be loading from a different location from attended robots, dont exactly remember that).
so what you need to do is change the robot setup to unattended from the orchestrator and then re-connect the robot. that would start a UiPath.ServiceHost which should be able to load the .nuget packages from the .nuget repository.

6

@golla.sandeep

First thing you need to install the robot in service mode..basically via custom setup

cheers

7

ah. right.. missed it.. thanks!

1 Like
8

I did that but it did not help either. I think the issue is with this UiAutomation.Activities.25.10.16 specific package. I tried to run other processes on unattended bot with same set up but without this version of uiautomation activity and it worked. Unfortunately I have developed the whole process with UiAutomation.Activities.25.10.16 version and downgrading is messing up with my activities.

9

Could you try downgrading your Studio to 24.* and try to publish the package again.

10

Apparently another package “videorecording” was causing the issues on VM, on removing that package everything worked perfectly..

11

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