import of freshly exported appliance fails

[MatsWolpers]

i am migrating from one host to another. on OLD machine, I export using standard/default settings in 6.0 (Mac OS 10.15) i transfer to NEW machine via usb-Disk i call import with default settings. a popup appears declaring that appliance <somename>.ova could not be imported. Error Code NS_ERROR_INVALID_ARG (0x80070057)

There seems to be a size dependency: i was able to import one appliance with size 5,62GB, several others larger than 10GB all fail.

There is of course no space problem on the NEW machine, there are more than 500GB free. FWIW, i detect nothing of interest in the system logs.