I am having this problem after updating windows where all photos in lightroom appear underexposed. When viewed from windows explorer OR when exported from lightroom they appear correctly exposed. I already tried to re-install both lightroom and photoshop but the problem persists.
Could you please try unchecking "Use Graphics Processor" from Lightroom's Preferences > General then relaunch Lightroom and let us know if it helps?
Actualy I don’t even have this option. im using Lightroom 2015 and maybe this option does not exist. Any other recommendations?