Problem exporting in Photo V1

[LisaR]

I'm running Affinity Photo V1 on Windows 10. I've never had a problem exporting until recently. It doesn't matter which export format I choose (I've tried them all), the resulting image has random lines throughout it (see attached image) where pixels are erased, and also areas where there are black lines. I try to export again, not making any changes, and the resulting image is the same but the random lines are different but still there. These lines are also appearing in the navigator box, even though the layer I'm working on looks fine. What is going on and how can I fix it?

[carl123]

Goto...

Edit > Preferences > Performance 

and switch off Hardware Acceleration

[LisaR]

That appears to have worked! Thank you so much!