The term 'M' discussed in the note refers to valuation indicator (M- Valuation with reference to the special stock & A- Valuation without reference to the special stock).and ‘E’ refers to consumption posting (E-Accounting via Sales order & P- Accounting via Project).
The root cause defined is inappropriate consumption indicator used in the account assignment category. Allowed entries are E & P.
Suggestion given:
If we want to enable goods movement takes place through the sale order stock then we must specify the valuation indicator 'M' (or) 'A 'depending upon our requirement and should use consumption indicator 'E' in the account assignment category.
If we want to enable goods movement takes place through the project stock then we must specify the valuation indicator 'M' and should use consumption indicator 'P' in the account assignment category.
For non-valuated stock the valuation indicator should be blank and use the consumption indicator 'E' (or) 'P' depending upon our requirement.