Hi! I don't yet have a reproduction recipe, but I think this is something that can be reproduced quickly. I'm on Mac OS X, using git 1.6.5.2. On branch master I have a file named public/clippy/clippy.hx. I created a new branch from master, named ticket-726. On this branch, I replaced public/clippy with a new version, where clippy.hx was renamed to Clippy.hx (note capital C). Merging with --no-ff from ticket-726 onto master results in: $ git merge --no-ff ticket-726-clippy-from-page Removing public/clippy.swf Removing public/clippy/clippy.hx Removing public/clippy/config.md Removing public/clippy/library.swf Removing public/clippy/swfmill Merge made by recursive. fatal: unable to read files to diff After this, the tree is unclean: $ git status # On branch master # Your branch is ahead of 'origin/master' by 9 commits. # # Changed but not updated: # (use "git add/rm <file>..." to update what will be committed) # (use "git checkout -- <file>..." to discard changes in working directory) # # deleted: public/clippy/Clippy.hx # If I merge without the --no-ff flag, the merge succeeds: $ git merge ticket-726-clippy-from-page Updating 8527f71..f9f070d Fast forward ... public/clippy/Clippy.hx | 45 +++++++++++++ ... public/clippy/clippy.hx | 28 -------- ... 21 files changed, 312 insertions(+), 79 deletions(-) ... create mode 100644 public/clippy/Clippy.hx ... delete mode 100644 public/clippy/clippy.hx ... Google didn't turn up anything, except the reference in the source code where this error message is defined. There was also a prior report of this bug http://collab.sakaiproject.org/pipermail/sakai-ux/2010-March/001058.html but I couldn't read anything interesting from it. As noted above, I'm on Mac OS X, which has is case insensitive, but case preserving. Thanks! François Beausoleil-- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html