I am a resident of California. I own a house in Massachusetts, and spend about 40% of the year there. No W-2 income, only pension and capital gains income arising from California investments. How do I enter this info? I see only a CHANGE of residence.

If you do not have Massachusetts income and did not change your domicile, you would not have to file a Massachusetts tax return.  A resident is a person who maintains a permanent place of abode in Massachusetts and spends more than 183 days of the taxable year in Massachusetts. 

Thanks for your response.  I have now deleted the other state residency entry on the federal personal info screen, but Turbo is still including the Massachusetts data in the "double taxed" entries.  How do I totally eliminate the Massachusetts data?

Delete you Massachusetts return. If you listed a second state of residency, TurboTax probably created a Massachusetts return.

Here's what to do in TurboTax Online:

1. Tap State in the left column
2. Select Your State Returns at the top
3. On Status of your state returns, tap the trash can next to Massachusetts