There might be a setting somewhere, but I do believe that SolidWorks skips at least some of those letters automatically (unless I did set this up a very long time ago and forget that I did so). I know my system skips I for sure, since I've seen that letter passed over many times.
Just did a test and found that SW skips I, O, Q, S, X and Z but if you need you can overwrite the view label. And after it finishes at Y, the next view label will be AA. To switch back it to A, right click on the sheet and select properties from the list. In the sheet properties window edit the "Next view label" to A or what ever is required.