My 1099-G box 10b has 17 characters and only 16 are allowed. Are you supposed to leave out the dashes? Then I will have 15 characters

[DoninGA]

Yes, leave off the dashes when entering the State Identification number in box 10b.

[Critter-3]

Which state ?  

[Opus 17]

10b is your participant number assigned by your state.  There is no mandatory IRS format, and 10b is not required for your IRS return.  (However, leaving it blank may confuse Turbotax.). There is no requirement that it be any exact number of characters, so try entering it without the dashes, it should not matter if is it less than the maximum allowable length.