Msg onscreen:Problem with your hard disc drive

[McAleny]

Often unable to switch channels and constantly need to switch off TV and switch on again.If I want to change channel later on, unable to do so.Back to repeat whole procedure again. Driving me mad!!

[Annie+UK]

Search for diskless mode in my Sky Plus FAQ

[Mark39]

You could try rebuilding your Planner, and if that doesn't help, a Full System Reset (which will delete your recordings. 

https://www.sky.com/help/home/sky-tv/sky-tv-plus/sky-plus-watching-sky-tv/sky-plus-recordings/articl...

It appears that your Sky box hard disk is on the way out, and if the above don't help, the box will need to be replace.

[TimmyBGood]

@McAleny 

Note that Sky will not themselves now replace an HD box, and will only offer migration to Sky Q (or Glass/Stream)

If you don't wish to do this, the last model (2015) Sky+ HD boxes are about £30 on eBay.