# Unknown signal error in adding device to PCB design **URL:** \ **Category:** Help\ **Created:** [June 19, 2026, 3:21am UTC](https://librepcb.discourse.group/t/unknown-signal-error-in-adding-device-to-pcb-design/1044 "2026-06-19T03:21:16Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![azural](https://avatars.discourse-cdn.com/v4/letter/a/a587f6/32.png) [@azural](https://librepcb.discourse.group/u/azural)\ **Post date:** [June 19, 2026, 3:21am UTC](https://librepcb.discourse.group/t/unknown-signal-error-in-adding-device-to-pcb-design/1044/1 "2026-06-19T03:21:16Z")
I was adding a device to the pcb editor when I got the error. "Unknown signal “f677ad9a-f589-4799-9ad-71bf43f94da” found in deviece “dfe9fe 19-3132-4dfb-8bc8-8ae04c80fb45"” ![image](https://global.discourse-cdn.com/free1/uploads/librepcb1/original/1X/704e74b3e698000196265304fad537e96bf10f9f.png) ---
**Author:** ![ubruhin](https://avatars.discourse-cdn.com/v4/letter/u/c89c15/32.png) [@ubruhin](https://librepcb.discourse.group/u/ubruhin)\ **Post date:** [June 19, 2026, 6:16am UTC](https://librepcb.discourse.group/t/unknown-signal-error-in-adding-device-to-pcb-design/1044/2 "2026-06-19T06:16:15Z")
Hi, It is very likely you made a breaking change to the component (in the library editor) after creating the device. I recommend to read [UUID References | LibrePCB Documentation](https://librepcb.org/docs/user-manual/references/) to understand the problem and how to avoid it in future. In your case it may be possible to fix it in the device editor. Open the TPS56520 device in the library editor, then you may see an invalid pinout. Correct the pinout and save the device. If this doesn’t help, you may have to remove the component from the schematic and re-add it afterwards. See also [Troubleshooting | LibrePCB Documentation](https://librepcb.org/docs/troubleshooting/#there-is-no-element-of-type)