After copy files to a pen drive all of them are corrupted

I'm trying transfer files from MacBook Pro with Mavericks to a pen drivers with FAT-32 and exFAT partitions

but unfortunately all files seems corrupted/encrypted so they become useless after paste them in the flash drives.

Why this is happening? I guess this could be regarding or related with the FileVault2 is enable in my SO?

I'm copy encrypted files to my flash drives?

Have someone ever seen this issue?

Thanks