  In various dimensional Euclidean lattice gauge theories, we examine a
compatibility of the Majorana decomposition and the charge conjugation property
of lattice Dirac operators. In $8n$ and $1+8n$ dimensions, we find a difficulty
to decompose a classical lattice action of the Dirac fermion into a system of
the Majorana fermion and thus to obtain a factorized form of the Dirac
determinant. Similarly, in $2+8n$ dimensions, there is a difficulty to
decompose a classical lattice action of the Weyl fermion into a system of the
Majorana--Weyl fermion and thus to obtain a factrized form of the Weyl
determinant. Prescriptions based on the overlap formalism do not remove these
difficulties. We argue that these difficulties are reflections of the global
gauge anomaly associated to the real Weyl fermion in $8n$ dimensions. For this
reason (besides other well-known reasons), a lattice formulation of the N=1
super Yang--Mills theory in these dimensions is expected to be extremely
difficult to find.
