Several users have complained of difficulties in reproducing the calculations and figures in the tutorial. The differences reflect various causes some of which are listed below: SPECIFIC DIFFERENCES/ERRORS: Chapter 3: The maximum temperature for the calculation should be 753 K, if you specify 873 K vertex will skip a curve segment unless you change the reliability level. Chapter 4: exclude sud and fath. Chlorite is not stable (or its stability is very limited) at the T (893 K) indicated for figure 4.1, lower the temperaure by ca 20 K. Chapter 5: exclude sud and fath. GENERAL DIFFERENCES: 1) The CORK equation of state for H2O-CO2 fluids has been changed since the tutorial was written. The effect of this change is minor, but may account for discrepancies of 10-20 K in the location of calculated phase equilibria. 2) Despite the fact that in most of the examples the text indicates that the hp94ver.dat data file was used, I suspect most of the calculations were in fact done with hp90ver.dat. Aside from changes in the data of individual phases, the newer data base includes data for phases like sudoite (sud) and ferro-anthophyllite (fath) that may destabilize the phase relations shown in the tutorial. As a rule, in doing the tutorial problems always exclude sud and fath. 3) For my own work, i sometimes create entries in the thermodynamic data files, such as "mthm" a oxygen buffer, for special problems. On occasion I have forgotten to delete such entries, which might destabilize phase relations for the tutorial problems. To my knowledge there are no such entries presently in any of the thermodynamic data files, but if you can't figure out what is going wrong and you find some suspicious phases you might try excluding them. 4) The subdivision schemes used in solut.dat have undoubtedly changed for many of the solutions used in the tutorial problems. This means you may not have exactly the same pseudocompound compositions as in the tutorial.