Import always terminates

When I want to import videos from my Virb Ultra 30, the import often stops. G-Metrix import works.

Details about my configuration:
Virb Ultra 30 with firmware 4.70
Samsung micro SDXC UHS-I PRO Plus 64 GB
Virb Edit 5.4.3
Windows 8.1 Pro 64bit

Videos mainly 1080p/50/wide

Automatic import or import of single clips makes no difference (cancel both).

Importing from Ultra 30 via USB cable or from SD card directly also makes no difference.

The SD card was formatted in the camera.

I used a SanDisk micro SD Extreme UHS-I before the SD card mentioned above. However, this card continuously caused interruptions during recording (SD card error). Finally the recording stopped 10 seconds before I was rammed by another vehicle :mad:
This SD card is recommended by Garmin for the Ultra 30. To exclude a defective SD card, I bought the Samsung.
Both SD cards tested and seem to be ok.

The videos can be played back easily from the camera and also on the PC.

Without import into Virb Edit I cannot use the G-Metrix data.

Does anyone have any idea how I could locate the cause?