Why is it checking spouse is not a taxpayer but dependent on parents and i correct it and it won't change and therefore won't let me file

[MichaelMc]

If your spouse's parents have already filed a tax return claiming them as a dependent, you are going to have to persuade the parents to file an amended tax return, without claiming your spouse, before you will be able to successfully file a joint return with your spouse.

The IRS needs ten weeks or longer to process an amended tax return, which must be submitted by mail.

At this point in the year, you would be well-advised to file for an extension of time to file, and wait until your spouse's parents' amended return has been processed, before filing your tax return.

Because of the conflict between returns, the IRS will not accept an e-filed request for extension. You should complete and print the extension request, Form 4868, to the IRS office serving your region. 

Where To File Form 1040X