cannot move VM from one PC to another

[52ROSt]

New PC
LM19.3 MATE
VB 6.0.4

Old PC
LM17.3 KDE
VB 5.1.14

Guest Machine WinXP

Attempt 1
Copying of complete folder from the old PC to an USB stick gives always the error and the copying process stops.

Could not write file/media/rost/8GBFat32_01/WFM Basic_01/WFM Basic-disk1.vmdk

rost=my PC name
8GBRFat32_01 = USBstick name, (GB, VM total files size is <7GB)
WFM Basic_01 is the name of the VM


Attempt 2
I exported the same VM into a folder at the old PC.
Copied it over to a USB stick
Copied it over to my new PC
Clicked Import and selected the exported machine
Used Mac Address Policy as default (Include only NAT network adapter MAC addressess
Addtional Options: Checked and Import hard drives as VDI
VM import works; no error messages or warnings
When I start the VM, I get the error message:

Could not start the machine WFM Basic_01 because the following physical network interfaces were not found:
eth0 (adapter 1), eth0 (adapter 2)
You can either change the machine's network settings or stop the machine.

Opened "Change Network Settings"
Adapter 1 and Adapter 2
Bridged Adapter
Name: enp0s25

As the roll-down menu shows 1 alternativ, I set both adapters to: wlp3s0
However, this seems not to be the solution because the OK button is still greyed out.
Thus I can only choose Cancel

Then I get the error message:

Failed to open a session for the virtual machine WFM Basic_01.
Nonexistent host networking interface, name 'eth0' (VERR_INTERNAL_ERROR).
Result Code: NS_ERROR_FAILURE (0x80004005)
Component: ConsoleWrap
Interface: IConsole {872da645-4a9b-1727-bee2-5585105b9eed}

After clicking OK, the start up process of the VM stops.

I appreciate a lot your help.

[socratis]

Copying of complete folder from the old PC to an USB stick gives always the error and the copying process stops.

That's not VirtualBox related, but my guess is that the USB stick is FAT32 and there's a size limit of 4GB for that filesystem.

Could not start the machine WFM Basic_01 because the following physical network interfaces were not found:

If you use Bridged networking, and that network adapter that you Bridged to in the original host, cannot be found in the new host, you're going to get this message. It's perfectly legal. You just need to re-Bridge it into an existing adapter on your new host.

However, this seems not to be the solution because the OK button is still greyed out.

That's because you have a setting that's invalid. There should be a triangle with a warning sign () in the bottom of the settings window. Hover over it and read the message. Take corrective action.