Windows 10 Problems - Crashes after about 15 seconds

I’m having problems with using mbed K64F and KL46Z boards under Windows 10. With the KL46Z boards they will run for about 20s or so and then windows probes them and the stored program is corrupted with the K64F boards, serial over USB communications will be lost although the LED keeps flashing which implies the program is still running.

The KL46Z boards have
MicroBoot Kernel Version is: 1.05
Bootloader Version is: 1.11
Application Version is: 0.00
i.e. the latest version when 20140530_k20dx128_kl46z_if_opensda.s19 is installed.

The K64F boards have

DAPLink Firmware - see

Unique ID: 0240000029304e45005e50027721001f9b01000097969900
HIC ID: 97969900
Auto Reset: 0
Automation allowed: 0
Overflow detection: 0
Daplink Mode: Interface
Interface Version: 0253
Bootloader Version: 0244
Git SHA: 64359f5c786363065a41ec15c348e3d53568da03
Local Mods: 0
USB Interfaces: MSD, CDC, HID, WebUSB
Bootloader CRC: 0xca4adf2f
Interface CRC: 0x08858a9a
Remount count: 0

I’ve installed the
driver multiple times.

The version of Windows 10 is Windows 10 Pro 1903 - 64 bit version

Has anyone any suggestions of what’s wrong and how to fix it?

Best wishes,


Hi Jeremy,

It seems that you can download the firmware to the boards? Both K64F and KL46Z are visible as diskdrive (DAPLINK something)?
Could you try another PC to isolate whether the problem is in the boards or in the PC?

If the problem seems to be on the boards you can update DAPLink from here:
Find FRDM-K64F for K64F and
FRDM-KL46Z for KL46Z.


Hello Pekka,

Many thanks for getting back to me.

Updating the KL46Z boards using the 0253_k20dx_frdmkl46z_0x8000.bin does seem to have solved the problem with the program corruption on the KL46Z Boards.

Just to add that I couln’t find anything to update either the KL46Z or the KL25Z from showing “bootloader” to “maintenance” as indicated on
as on that page the KL46Z and KL25Z aren’t listed.

Now with both the KL46Z and the K64F boards under device manager I have listed under
“Other Devices” Web:USB: CMSIS-DAP with a yellow triangle and the Device status showing “The drivers for this device are not installed (Code28)” Is that an issue?

I’ll try on the problem machine tonight to see if it resolves the issues with the K64F on that specific computer.

Best wishes,


Hi Jeremy,

It shouldn’t be an issue. That interface is used only by WebUSB to allow to access a device from the browser. It is broken as it is incompatible with a serial driver you installed. It is worth pointing out that this driver should not be needed on Windows 10 to access serial. You can find this information here: