  The recursion operators and symmetries of non-autonomous, (1+1)-dimensional
integrable evolution equations are considered. It has been previously observed
that the symmetries of the integrable evolution equations obtained through
their recursion operators do not satisfy the symmetry equations. There have
been several attempts to resolve this problem. It is shown that in the case of
time dependent evolution equations or time dependent recursion operators,
associativity is lost. Due to this fact such recursion operators need
modifications. A general formula is given for the missing term of the recursion
operators. Apart from the recursion operators a method is introduced to
calculate the correct symmetries. For illustrations several examples of scalar
and coupled system of equations are considered.
