About 12th May, prompted by Mint's update icon ' ! ' , I did an update that, deleted many files. Since then lots --- not all --- of what used to be black print on a white background have become white, just discernible, while print on the same background. Examples are text on Gedit --- though \TeX and other after ' \ ' instructions in TeX show up green as usual; the name of files in Files; the score - but not the 'New, ... Quit' menu for "Five in a line. Text in websites is as I'd expect. Similarly Thunderbird works as always. Help welcome, help needed! (I've not been able to think of anything to try although I've looked, using Syaptic, for files that might be worth installing & come up against loads of dependency and depository problems. Help needed!