When copying a file name that contains a bar character, like "file | name.txt", to a USB drive the following error appears: Failed to copy "/home/podderka/dump/file | name.txt" to "/media/disk/docs/file | name.txt". Failed to open "/media/disk/docs/file | name.txt" for writing (Invalid argument). Do you want to skip it? I assume the reason is because the bar acts as a pipe. To reproduce error: 1. Create file on hard disk with the name containing '|' (without the quotes). 2. Copy file to USB drive.
No, I'd guess you're using a FAT32 file system for the USB drive, which cannot handle file names with certain characters.
Please reopen if this is still an issue with the latest Thunar release.