Hello,
after 1 Day search for the reason, why my big Rar Archives are getting corrupted .
I have network problems excluded, then a faulty Ram, and come to the conclusion, after the deinstallation of NOD32 AV, it was the AV. (Actual NOD Version from Eset from Sunday).
The Size per Archive was different, to the other (example: 250.552 correct was 250.550 Kbyte). And Powerarchiver/Winrar/7-Zip told me, the Rar has an "unexpected end"..