When using the Windows IoT Core Image Helper tool to deploy a Windows 10 IoT Core image (.ffu file) on a microSD card, the following error can happen :

If you encounter this error ("There were come errors while loading Windows IoT Core onto your SDCard."), the most probable cause is that your microSD card size is less than 8GB.
In the Get Started page, it is said that a 8GB micro SD card is required. However, it used to work wit a 4GB one in the previous drops. So be aware that you need to change it if you used to work with a 4GB one.
When using the right hardware, the deployment of the image runs smoothly.
The first time you will make your system boot with this image, it will take a long time. You will probably be confronted to a five minutes long black screen. This is completely normal, and will only happen the first time. Do not try to reboot your system during this time !
Enjoy!
- Nicolas & Leo