And.....It's back
Ran all day yesterday, not a hint of trouble. Tonight I had one quick job and this time I get no tool length compensation.
The error message this time was "scripter compile error in M6End.m1s" - this is why no TLC as that is in my M6End macro.
Now, last time the M3.m1s played up I saved it as M3.mcc which i believe is pre-compiled?
Seems odd that it now failed on the M6 macro - I have now saved both M6Start & M6End as .mcc files - in the vain hope that it will stop it doing it again. Of course there will always be another macro to fail I guess.