Errors & Troubleshooting

Occasionally the editor or app you are using will throw an error. Common errors are listed here with a description of what they mean and what you can do to resolve them.

0kb .HEX file
If your .Hex file appears to compile and download, but results in an empty (0Kb) file it is likely due to lack of storage on your device. If you are downloa...
Tue, 5 Mar, 2019 at 9:14 AM
Program Error: sim error: failed cast on null
Description This error occurs when in the MakeCode editor simulator when it is trying to process the program and there is an error in the code. This is usu...
Wed, 16 Aug, 2023 at 12:43 PM
How to get the current program off the micro:bit
There may be occasions when you want to take a look at the programming that is running on the micro:bit or if you have misplaced the original program. To do...
Thu, 27 Aug, 2020 at 8:16 AM
Python OSError Codes
A list of Python OSError codes and descriptions raised when a system operation causes a system-related error, including I/O failures such as “file not found...
Thu, 20 May, 2021 at 2:36 PM
Finder Error 100093 when using drag and drop to transfer a micro:bit .hex file
Alert for MacOS 13 Ventura users only: Any user attempting to use the drag and drop option to transfer a micro:bit .hex file using the Finder application o...
Wed, 8 Nov, 2023 at 11:25 AM
Using a micro USB cable with an Android device
The micro:bit is supplied with a cable that has micro USB type B on one end (this connects to the micro:bit) and USB-A on the other end (designed to connect...
Tue, 19 Dec, 2023 at 10:29 AM