What does this mean

It happens with most tablets Petra I use an iPad and a Kindle-fire and yes, it's a learning curve.

Thank you, everyone. I am using an iPad. I have cleared history and it seems to be ok. Must do this more often. Lesson learnt.

Are you using a tablet, a laptop or a PC?

I'd say clear out some of files you have open that are clogging up your operating system.

I'm not at all sure what it means but Safari does get its knickers in a twist from time to time and comes up with this message. Try deleting History. If that doesn't work, try restarting your computer.