- First off please ensure you are running the latest version 6.3(Check from Help>>About Lightroom ).
- Open Lightroom >>edit>>Preferences>>Performance
- Uncheck "Use Graphics Processor"
- Restart Lightroom
If still the same refer the section "Manually disable graphics card in Adobe Lightroom GPU Troubleshooting and FAQ
Thanks for your reply.
I know that I have upgraded to latest.
Will disabling graphics card slow my pc?
Seeing how Lr is a graphic program it seems odd to have to disable graphics card when it's never been an issue in the past but I will try that when I get home later today.
If the entire computer is freezing and you have to reboot the computer, then this is a hardware malfunction somewhere (could be bad memory, could be overheating due to fans that stop working, or possibly a few other things), or a bad/corrupted video card driver. You need to update/reinstall your video card driver and check all hardware components for malfunctions.