FreeBSD wombat 11.2-RELEASE-p4 FreeBSD 11.2-RELEASE-p4 #0: Thu Sep 27 08:16:24 UTC 2018 root@amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64 Short description: drag&drop a file from a rox-filer window showing the hard drive to a rox-filer window showing an USB drive. If the file already exists on the target drive, it will be truncated. Expected behaviour: The existing file on the USB drive should be overwritten. Long description: After logging in, I start an Xfce session manually: startxfce4 --with-ck-launch mount stick in an xterm, as per handbook. Note that I've set up user mounting of USB drives: mount -t msdosfs -o -m=644,-M=755 /dev/da0s1 /stick/username open source directory (on hard drive) in a ROX-Filer window open target directory (on usb drive) in another ROX-Filer window drag&drop a file from source over an existing copy of that file on target dialog box asks if it is ok to overwrite which I agree to ROX-Filer window shows the expected file size immediately after copying, and after rescanning the directory. ls -al /stick/markus/targetdir also shows the expected file size at this point. umount /stick/markus. fstat shows that the ROX-Filer process keeps the mounted directory busy, so I need to close all ROX-Filer windows first or kill the process in order to umount cleanly without -f. then mount the stick again as above, or try on a different computer ls -al /stick/username/targetdir shows a target file size of zero. Expected behaviour: the target file should be overwritten. If the stick is unmounted properly, pending data should be flushed, and no data should be lost. Ever. Additional information: ROX-Filer works correctly on a Debian Linux box, so it might be no ROX-Filer bug per se. Also, I cannot recall having this problem before I updated to FreeBSD 11.2. Target files are not truncated if I use Thunar or cp to overwrite existing files on the USB drive. Any help is appreciated.