Can you check out this page:
https://www.ftb.ca.gov/file/business/types/sole-proprietorship.html
Points of interest from their website:
Part-year and nonresidents
For part-year residents or nonresidents, California source income includes, but is not limited to:
AND:
A nonresident operating a sole proprietorship with California source income must file California Nonresident or Part-Year Resident Income Tax Return (Short Form 540NR) or (Long Form 540NR).
Let me know what you think based on what this site says. While it sounds like they DO require I file, I have no idea why on earth this can be legal for them to require me to pay double taxes on the same income. GA already got my tax money, naturally, on that income. I live here! They have a right to it. Just like CA gladly charged me taxes on my NC income when I was a resident of CA. (NC did NOT ask me to also pay them since I lived and worked in CA back then!)
But if what CA is asking for, is legal and they can charge us, what's to stop all the other states that have people who paid me from requiring me to file in their states too for that year or other past years? (TN, NC, VA and AZ to name a few.)
The last thing I want to do is give CA more info than they should have access to, either.
