Question : Remove Recurrence button is greyed out for outlook tasks can not delete

I cannot remove a recurring task. The "remove recurrence" button is greyed-out.

Answer : Remove Recurrence button is greyed out for outlook tasks can not delete

I figured it out.
Here are the instructions in case someone else has this problem:
1) Open the task that is recurring
2) Click on the "recurrence" button
3) Change the 'end date' option from 'no end date' to 'end after 10 times'
4) Click OK
5) Click the "recurrence" button again
6) The "remove recurrence" button should now be enabled
7) Click "remove recurrence"
8) Click OK
9) Save and close

Hope this helps someone.