Block Designer
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Windows · Beta

Windows setup & troubleshooting

Two one-time hurdles can come up the first time you run Block Designer and flash a board: the unsigned build is blocked on first run, and the ST-LINK needs its USB driver set up. Both are quick — this page walks through each.

1. First run blocked by Windows

Block Designer isn't code-signed on Windows yet, so Microsoft Defender SmartScreen shows a blue “Windows protected your PC” warning the first time you run it. The clip below shows the whole flow, start to finish:

Running block_designer.exe and getting past SmartScreen with More info → Run anyway.

Step by step:

  1. If your browser warns about the download, choose Keep / Keep anyway.
  2. Extract the zip and double-click block_designer.exe.
  3. On the SmartScreen dialog, click More info, then Run anyway.

You'll only need to do this once.

2. “Debug probe could not be created” when flashing

The ST-LINK is detected but won't open — on Windows this is a USB driver issue. Block Designer's flasher needs the WinUSB driver bound to the ST-LINK. The clip below shows the whole fix in Zadig, start to finish:

Binding the WinUSB driver to the ST-LINK in Zadig, then flashing again from Block Designer.

Step by step:

  1. Download Zadig.
  2. Plug in your board, run Zadig, and pick the ST-Link device from the list.
  3. Choose WinUSB as the target driver and click Replace Driver.
  4. Reconnect the board and try flashing again.
First check: make sure no other tool (e.g. STM32CubeProgrammer) is holding the probe — close it before running Zadig.

More detail in the probe-rs setup guide.

Still stuck? Open a discussion or file an issue — happy to help.