Calculate Automatic keeps changing to Manual

[JUhlman07]

While using excel, the formulas usually calculate automatically, the past few weeks when opening different worksheets and entering formulas, I have to manually calculate each field, unless using the F9 function. The settings under option, for calculate keep changing from Automatic to Manual everytime I log off of my computer. Are there any tips on how I would get this to stay, or the reason it continues to change?

[jasoncw]

Do any of the files you work with contain macros? If so, there may be a script in there to change calculation to manual.