File access for external USB (EXT4)

[Irondy]

Hello,

I attached an external USB drive to the NAS and got access to the filesystem.

The extract from the mount looks like this:
...
/dev/sdf1 on /share/USB11 type ext4 (rw,relatime,data=ordered,jqfmt=vfsv1,usrjquota=aquota.user,grpjquota=aquota.group)
...

Unfortunatly sometimes I got the following error message from the NAS (copying files with cp *):
cp: can't stat '/share/USB11/Video/ARD-Jahresrückblick 2016_20170101_1137.ts': No such file or directory

I'm unable to list, access or copy those files which includes some umlaut in the filename.

Any idea how to access those special files?

[orion]

Not sure if it's caused by illegal characters. Did you try to "cp" those file under Ubuntu system?