Blue square with white cross

[MyFather_sWorld]

Happily editing and suddenly a blue square keeps flashing up which is very distracting - why?

[dj_paige]

Is this a Lightroom question?

Can you show us a screen capture?

[99jon · Accepted solution]

Have you tried disabling GPU acceleration? Let us know if that makes a difference.

Go to:

Edit >> Preferences >> Performance (tab)

Lightroom >> Preferences >> Performance (tab) on Mac OS

Uncheck the box “Use Graphics Processor”

Then click OK