I cancelled the import. after that i made a new scan. at the start of the scan in the bottom 3219 error. in dutch: De bewerking is in deze context niet toegestaan. I a rough translation: This edit is not allowed in this context.
It found 0! movies. and i know i have 20 in the folder. all in a new directory MKV file no special characters. (movie name.mkv)
It seems that when the error occurred there is some way that the scanning was interrupted. And the only way to recover for it is to stop scanning (it has no use because no movie will get imported) Close XMM and reopen XMM.
And hope there will be no screen so the import will go perfectly :)