Upon installing LO 25.2.3.2 in Apple silicone iMac, I manually corrected my templates’ background color from black (hex 000000) to white (hex ffffff). However, all calc sheets previous to that installation are cluttered with random blocks of blacked-out cells.
Manually formatting the background color of blacked-out blocks from black to white does restore calc readability.
As my calc document has many thousands of entries, manual restoration is untenable.
Is there a background color test to automatically convert cell background color which is not dependant on cell numerical value ?
Thanks ! Rob Glass
an example would help 
Test if changing the Appearance>Theme could help, sometimes after install 25.2 changing the Theme applying it, solves the issue.