Missing Activities in UiPath Studio 23.4.X Despite All Dependencies Being Installed

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How to resolve missing activities in UiPath Studio 23.4.X despite having all dependencies installed?

Issue Description

Some developer users have reported an issue where:

  • Certain projects are missing activities inside the workflow even after successfully installing all project dependencies.
  • Error messages such as "Could not find type" or "Could not resolve type" are thrown in the UiPath Studio Output Panel.

From the UiPath Studio Designer and Output Panel, below is an example of how the errors appear.

Example.jpg
Example.jpg1112×598 84.9 KB

Example2.jpg
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Confirmation Steps

From the UiPath.Studio.log file located inside the %localappdata%\UiPath\Logs\ YYYY-MM-DD_UiPath.Studio.log the errors thrown are the following.

[ERROR] [UiPath.Studio] [8] Unrecognized signature of file C:\Users\RobotUser1\.nuget\packages\UiPath.Platform\24.12.2\.signature.p7s:
[WARN] [UiPath.Studio] [8] Skipped package UiPath.Platform from feed Orchestrator Host, signature check failed
[ERROR] [UiPath.Studio] [8] Unrecognized signature of file C:\Users\RobotUser1\.nuget\packages\UiPath.Platform\24.12.2\.signature.p7s:
[WARN] [UiPath.Studio] [8] Skipped package UiPath.Platform from feed Official, signature check failed
[ERROR] [UiPath.Studio] [28] Failed second time to update the platform assembly: Restored version: 24.10.2, Project.exe version: 23.4.1
[WARN] [UiPath.Studio] [26] Restored version: 24.10.2, Project.exe version: 23.4.1
[ERROR] [UiPath.Studio] [36] Unrecognized signature of file C:\Users\RobotUser1\.nuget\packages\UiPath.Platform\24.12.2\.signature.p7s:
[WARN] [UiPath.Studio] [36] Skipped package UiPath.Platform from feed Orchestrator Host, signature check failed
[ERROR] [UiPath.Studio] [36] Unrecognized signature of file C:\Users\RobotUser1\.nuget\packages\UiPath.Platform\24.12.2\.signature.p7s:
[WARN] [UiPath.Studio] [36] Skipped package UiPath.Platform from feed Official, signature check failed
[ERROR] [UiPath.Studio] [35] Failed second time to update the platform assembly: Restored version: 24.10.2, Project.exe version: 23.4.1

After confirming this, it is expected that errors related to missing activities will appear a few lines below in the same file (the same errors as in the output panel), as shown below.
Important Note: These errors may vary in each case, as they are related to the specific activities within each workflow 

[ERROR] [UiPath.Studio.App.Logging.OutputLogger] [1] Could not find type 'InvokeWorkflowFile' in namespace 'http://schemas.uipath.com/workflow/activities'. Row: 166, Column: 16
[ERROR] [UiPath.Studio.App.Logging.OutputLogger] [1] Could not resolve type 'http://schemas.microsoft.com/netfx/2009/xaml/activities:Catch(BusinessRuleException)' because could not find one or more of its type arguments. Row: 179, Column: 14
[ERROR] [UiPath.Studio.App.Logging.OutputLogger] [1] Could not find type 'BusinessRuleException' in namespace 'http://schemas.uipath.com/workflow/activities'. Row: 179, Column: 14
[ERROR] [UiPath.Studio.App.Logging.OutputLogger] [1] Could not resolve type 'http://schemas.microsoft.com/netfx/2009/xaml/activities:ActivityAction(BusinessRuleException)' because could not find one or more of its type arguments. Row: 186, Column: 16
[ERROR] [UiPath.Studio.App.Logging.OutputLogger] [1] Could not find member 'Argument' in type 'http://schemas.microsoft.com/netfx/2009/xaml/activities:ActivityAction'. Row: 187, Column: 18
[ERROR] [UiPath.Studio.App.Logging.OutputLogger] [1] Could not resolve type 'http://schemas.microsoft.com/netfx/2009/xaml/activities:DelegateInArgument(BusinessRuleException)' because could not find one or more of its type arguments. Row: 188, Column: 20
[ERROR] [UiPath.Studio.App.Logging.OutputLogger] [1] Could not find type 'LogMessage' in namespace 'http://schemas.uipath.com/workflow/activities'. Row: 294, Column: 28
[ERROR] [UiPath.Studio.App.Logging.OutputLogger] [1] Could not find type 'AddLogFields' in namespace 'http://schemas.uipath.com/workflow/activities'. Row: 461, Column: 16

Affected Versions

  • All 23.4.X versions (both service and user installations).

Fixed Versions

  • From version 23.10.0 onwards, this code section was reworked, and the bug no longer affects these versions.

Root Cause

This issue is caused by a bug in UiPath Studio version 23.4.X, where the project requests a version of UiPath.Platform newer than the bundled or cached version.
The "Unrecognized signature of file" error is thrown because Studio version 23.4.X is unable to recognize the latest certificate signature for UiPath.Platform 24.12.2 located in the selected package installation folder.

Resolution

  • Update to a Fixed Version (Recommended)

The code section responsible for this issue was reworked in version 23.10.X (and higher). The issue no longer occurs in these versions.
If possible for the organization, it is recommended to update to UiPath Studio version 23.10.X or later for a permanent fix.
The installer can be downloaded from the Resource Center in UiPath Automation Cloud or provided by your customer success manager or the support team. The latest 23.10.10 version is available here.

  • Workaround (if unable to update Studio)
If updating is not immediately possible, follow the steps below as a workaround:
    1. Obtain this file from a machine with UiPath Studio 23.10.X or higher by navigating to %userprofile%\.nuget\packages\uipath.platform\24.12.0
    2. Move the file to the Uipath Studio machine with issues.
    3. Close all Studio instances.
    4. Move the .signature.p7s to the %userprofile%\.nuget\packages\uipath.platform\24.12.0 and replace the current file.
    5. Reopen the target process.

Notes:

  1. This workaround must be performed for each user on the affected machine.
  2. It might be necessary to apply the same process to other directories within uipath.platform\24.12.0, for example, for version 24.10.2.