I have a problem with FritzWlan stick and I was wondering if it's damaged or do I do something wrong. When copying large files from my PC to NAS or back, they sometimes end up corrupted and Windows does not even display any error message. It seems to happen particularly often with large files. After I switched from FritzWlan Stick to an Ethernet cable the problem disappeared. My configuration is Windows 10, new Synology NAS, standard router from UPC, all updated, etc.