I lived in my house & used home office for 2 yrs, so my "placed in service" date is 1/2017. Then I purchased my home in 9/2018, the date I acquired my asset (my home).

[smith78223]

It is forcing me to backdate the date of acquisition of my home (9/28/18) to the date my home office was placed in service (1/1/17).  I rented my home for 2 years before buying it.  But I really didn't acquire it as an asset until 9/2018.  So which date do I use?  Do i have to change the date placed in service of my home office?  I have been using my same house as a home office for 2 years while I rented it.  

[CaronM]

You would want to use the date of purchase as the "placed in service" date. This will allow you to start depreciating the home office.