Occasionally, I've yet to establish if there's any pattern to this, kdesu fails.

For example:

I may start an application that requires root privileges, YaST2 for instance.

Normally the password dialogue for kdesu appears, password is entered and Yast2 (or whatever) is launched.

On some instances all that appears is the 'bouncing cursor', which eventually times out, kdesu is not started.

From this point on kdesu will not work until one logs out/in.

or... discovered by trial and error...

The kdesud process is killed, at which point it restarts and the kdesu password dialogue appears and all is back to normal.

I've seen this with several versions of KDE (currently using Platform Version 4.14.2) and have just 'lived with it'.

When it 'fails' it seems to do so silently... I've yet to find any error messages.

Curious as to whether anyone else has seen this, or, better still has a solution. Maybe a bug report is in order.

Never encountered this, but would suggest to just gdb into kdesud to check where it mumbles around

OK thanks...

I'll have to wait for it to happen and have some spare time to investigate.

Since making the original post I've found this bug report https://bugs.kde.org/show_bug.cgi?id=208979 which is _suspiciously_ similar to the effect I'm seeing.