My TV is a UE40KU6000, with software version 1165.
There is at least one other thread on this topic (see “Update 1160.6 black screen on start”, 29-01-2017). It concerns an earlier version of the software but the workaround it presents was equally effective on my version. However, I didn't find this until after I had solved the problem by lengthy trial and error, so I thought it might be useful to share a new thread with different keywords, and to extend the description of the symptoms.
I bought my TV in November 2016. Until a few weeks ago it worked perfectly, then this symptom appeared:
On startup, instead of defaulting sensibly to the last channel viewed, it would often display a blank screen, compelling me to go to the source menu to select live TV.
I did some testing and found another problem:
The TV often failed to record scheduled programs to a USB memory stick.
Both these symptoms were time dependent. If I switched the TV back on after a few hours it would usually default to the last channel, but switching on the next day always produced a blank screen. Similarly, scheduling the recording of a program that was to be broadcast within a few hours usually worked, but scheduling for the next day always failed.
The workaround for both problems is to go to <Broadcasting>, <Auto Tuning>, <Standby Auto Tuning> and turn this function off.
I don't know the full history, but it looks as though Samsung introduced a new feature in version 1160 to retune the TV automatically once a day or so, and inadvertently broke a couple of other software functions in the process. It appears that the same fault is still being distributed months later in version 1165.
Could someone from Samsung clarify this situation please? The symptoms really do seem to imply a bug in the Standby Auto Tuning function, and the lack of any clear acknowledgement or corrective action is puzzling. I apologise if there is a response from Samsung somewhere that I've missed; if this is the case, can anyone provide a link?
I had the exact same problem.
Called Samsung 4 times and they had no fix.
5th time (last Saturday 11th March) they told me to turn off Standby Auto Tune and it has worked.
So looks like they are now aware of the problem which will hopefully be dealt with in the next firmware update.
THen all we'll need is All4.