Today I installed the LR 6.2.1 update for the update again. Just for fun. Meanwhile I was fallen back to LR 6.1.
What shall I say? It worked immediately without any problem so far on my Win-10 Dell-System. Graphic-Support is disabled.
Of course, the new import has to show whether it's useable in praxis at all. But that was the least problem besides the hangs, loops and crashes.
And, unbelievable, it seems faster than 6.1 !