If the method is still "set up," then Totalchrom will not let you make changes.
If your analysis is complete, you can go to the Admin tab at top, then Cam Administration drop down menu. Click on the instruments or users until you find where the method is locked. Select "remove cam lock" from the drop down Edit menu.
If the method is still in use (HPLC / GC running), then make a reprocessing copy of the method with "save as." Change the sequence Reprocessing column to the new method name before reprocessing data.
If the method is not locked, then it may be corrupted after being overwritten or saved from a previous method. In that case, try creating a method from scratch. I know this option is painful, but is frequently necessary in Totalchrom world.
Our PE field service engineer tells me to create a brand new sequence and method for every run due to the known issue with copying or reusing sequences and methods.
Hope this helps.