In reviewing the differences between 1.1.8 and 1.1.9 I saw a probable bug in the new function uint_cmp() in src/lib-storage/index/maildir/ maildir-sync-index.c: if (*i1 < *i2) return -1; else if (*i1 > *i2) return -1; else return 0; The second case should return 1 not -1.