# External Control URCapX fails to install on PolyScope X 74.23.218 (Manifest file missing)

**URL:** <https://forum.universal-robots.com/t/external-control-urcapx-fails-to-install-on-polyscope-x-74-23-218-manifest-file-missing/41546>\
**Category:** Robot Communication\
**Created:** [October 20, 2025, 5:29pm UTC](https://forum.universal-robots.com/t/external-control-urcapx-fails-to-install-on-polyscope-x-74-23-218-manifest-file-missing/41546 "2025-10-20T17:29:42Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sabrina.mekhoukh](https://avatars.discourse-cdn.com/v4/letter/s/db5fbb/32.png) [@sabrina.mekhoukh](https://forum.universal-robots.com/u/sabrina.mekhoukh)\
**Post date:** [October 20, 2025, 5:29pm UTC](https://forum.universal-robots.com/t/external-control-urcapx-fails-to-install-on-polyscope-x-74-23-218-manifest-file-missing/41546/1 "2025-10-20T17:29:42Z")

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Hello everyone,

I’m currently setting up a **ROS 2 Jazzy** environment with a **UR7e** robot (e-Series, manufactured recently – August 2025).  
The robot is running **PolyScope X version 74.23.218**.

When I try to install the **External Control URCap X** (required for ROS 2 control) I get the following error message on the Teach Pendant:

> `Cannot install URCap`
> 
> ![Screenshot from 2025-10-20 14-28-45](https://us1.discourse-cdn.com/flex020/uploads/universal_robots/original/2X/a/a3da5ba050eb0f6b6901f799b7c868a28d5e8e4c.jpeg)
> 
> `: Manifest file (META-INF/MANIFEST.MF) is missing`

Steps I followed:

1. Downloaded `externalcontrol-0.1.0.urcapx` from the official GitHub release page:  
[https://github.com/UniversalRobots/Universal\_Robots\_ExternalControl\_URCapX/releases](https://github.com/UniversalRobots/Universal_Robots_ExternalControl_URCapX/releases)

2. Copied the file to a USB stick (root directory).

3. Installed via _Settings → System → URCaps → + (Add URCap)_.

4. The error appears when i select the file (external-control-0.1.0.urcapx).

I double-checked the file name and integrity, but PolyScope still refuses to install it.  
It looks like my robot expects a **newer, signed URCapX package format** for the 74.x firmware.

**My questions:**

- Is there an updated version of the _External Control URCap X_ compatible with **PolyScope 74.x**?

- If not yet released, is there any workaround (for example using **RTDE** directly with the ROS 2 driver)?

- Should I request a signed URCap package from UR Support?

Any feedback or confirmation from users running PolyScope X 74 would be greatly appreciated! 🙏

Thanks in advance for your help.

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**Author:** ![Florian.Wolff](https://avatars.discourse-cdn.com/v4/letter/f/c67d28/32.png) [@Florian.Wolff](https://forum.universal-robots.com/u/Florian.Wolff)\
**Post date:** [January 21, 2026, 11:53am UTC](https://forum.universal-robots.com/t/external-control-urcapx-fails-to-install-on-polyscope-x-74-23-218-manifest-file-missing/41546/2 "2026-01-21T11:53:35Z")

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Hi Sabrina,

sorry for a very late reply, but I just stumbled upon this topic and wanted to still provide an answer for anyone else looking at this.

From the Screenshot it looks like you are trying to install a PolyScope X URCapX File onto a PolyScope 5 System. This can not work. You will need to download the PolyScope 5 External Control URCap with the Ending “.urcap”