I started from beginning (from factory image) - everything is ok now.
I found a problem with flashdrives and sd memory cards on my new Vostro 5471 laptop. I have Windows 10 Pro ver. 1709. If drives has FAT32 file system, I have message that drive is not formatted. All drives are ok, they work on other PC with no problems. If drives has NTFS filesystem - everything is ok. I have newest BIOS (from 21 Febr. 2018) Could anyone help me?
Flashdrive/SD-Card with FAT32 problem