Startup issue: Unknown file system, you need to load the kernel first

To preface, the universal robot I have boot up fine yesterday.

Today, when trying to boot the computer, the black and white screen appeared displaying a message:
“Unknown file system. You need to load the kernel first”

Does anyone know how to fix this issue? I’ve been trying to fix this for hours and nothing has changed since the issue has first appeared.


Did the SD card pop out?

No. I even unplugged it and plugged it back in and it didn’t change anything.

My first thought as well. Thats the issue i had with my 2nd bot. SD card was not seated 100% perfect.

We found that the solution was to reinstall the PolyScope image. Something on the SD card got corrupted somehow. The SD card itself might be bad too and will be replaced.

How to replace flashcard in CB3 robots 15375 - UR Support (

We skipped any data backup steps but the second PDF in the link above provided instructions on how to install a new image.

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Ouch, hope you didn’t have too much on there. In the future there are windows programs you can use to pull files off of the Linux file system on the SD.

I use the Diskinternals linux FS reader but there are a bunch of others too. Might even be able to do it with WSL.