[boost] Cannot add any file to GIT "libgit2 returned: Invalid data in index - invalid entry"

Cannot add any new file to GIT repo :-( "libgit2 returned: Invalid data in index - invalid entry" Have recently locally committed changes to an existing Boost.Math sub-module (commit OK). (But realized that I had forgotten to add a few new files, so tried to add and recommit, but failed at the add stage). git status shows expected untracked files and ends: nothing added to commit but untracked files present (use "git add" to track) I:\modular-boost\libs\math> .gitignore is the standard modular-boost issue and looks OK. I:\modular-boost\libs\math>git version git version 1.9.5.msysgit.0 Suggestions? Thanks Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830