Hi again!

It all works perfectly well.

This is the function I used:
=IF(ISNA(VLOOKUP(H2;CYBEX_Bestand!$O$10:$P
$11392;2;FALSE))=TRUE;VLOOKUP(VALUE(H2);CYBEX_Best and!$O$10:$P
$11392;2;FALSE);VLOOKUP(H2;CYBEX_Bestand!$O$10:$P$ 11392;2;FALSE))

I copied the columns with the check values to the right according to
what Mike said:
"VLOOKUP looks up the first column and returns a column to the right,
It
can't work the other way around [...]"

Thanks to both of you, Bob and Mike!

Best regards

Thommes