Hi Larry,
I also use Goldwave for the same purpose and have never experienced your problem.
Just a suggestion - The WMA option is the last option in the 'Save as Type' pull-down menu and you have to scroll down to see it.
Even though you have obviously used the program dozens of times, could it be that you are having a 'Senior Moment'
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If this is not the case, then you could always try re-installing the program.