Thought I'd share this in case anyone else trips on it.
Windows allows spaces in usernames. If you are trying to map a CIFS/SMB share in the UI you have to put quotes around the username otherwise you get a malformed mount command and the "error" below. Seems like it would be simple enough for the UI to check for spaces and add quotes but that's not how it seems to work.
Usage: mount [-lhV] mount -a [options] mount [options] [--source] | [--target] mount [options] mount [] Options: -a, --all mount all filesystems mentioned in fstab -c, --no-canonicalize don't canonicalize paths -f, --fake dry run; skip the mount(2) syscall -F, --fork fork off for each device (use with -a) -T, --fstab alternative file to /etc/fstab -h, --help display this help text and exit -i, --internal-only don't call the mount. helpers -l, --show-labels lists all mounts with LABELs -n, --no-mtab don't write to /etc/mtab -o, --options comma-separated list of mount options -O, --test-opts limit the set of filesystems (use with -a) -r, --read-only mount the filesystem read-only (same as -o ro) -t, --types limit the set of filesystem types --source explicitly specifies source (path, label, uuid) --target explicitly specifies mountpoint -v, --verbose say what is being done -V, --version display version information and exit -w, --rw, --read-write mount the filesystem read-write (default) -h, --help display this help and exit -V, --version output version information and exit Source: -L, --label synonym for LABEL= -U, --uuid synonym for UUID= LABEL= specifies device by filesystem label UUID= specifies device by filesystem UUID PARTLABEL= specifies device by partition label PARTUUID= specifies device by partition UUID specifies device by path mountpoint for bind mounts (see --bind/rbind) regular file for loopdev setup Operations: -B, --bind mount a subtree somewhere else (same as -o bind) -M, --move move a subtree to some other place -R, --rbind mount a subtree and all submounts somewhere else --make-shared mark a subtree as shared --make-slave mark a subtree as slave --make-private mark a subtree as private --make-unbindable mark a subtree as unbindable --make-rshared recursively mark a whole subtree as shared --make-rslave recursively mark a whole subtree as slave --make-rprivate recursively mark a whole subtree as private --make-runbindable recursively mark a whole subtree as unbindable For more details see mount(8).
