I moved mid year and am self employed and home office. The transition from one home office to another was pretty seamless. How do I let Turbo tax know this? It seems to think I had 2 offices at once!

You *WILL* have two home offices (HOs) when done, listed on the return.

First, you must close the hold home office. The program asks something like "Did you stop using this asset in 2017?" Answer yes and work it through. Note that the date you stopped using it must be at least one day "BEFORE" you moved out. When it comes to your HO expenses, you only enter those expenses paid while that HO was open - usually the "whole house" expenses. So if you closed the HO on June 30th, you only enter your whole house expenses paid January through June.

When done closing the old HO, you will click the button to "Add Another Home Office" for the new residence. Note that your "in service" (start of use) date for the new home office must be at least one day "AFTER" you closed the old home office (those dates can't overlap) and must also be at least one day "AFTER" your move in date. Again, expenses for the new home office need to be those paid for the period of time *THAT* HO was open.

You will enter them as they were used without concern for the other.

So if you had 2 businesses that you had a home office in both your old home and your new home, you would enter the home office the same way for each business.  You will enter that you used XYZ address for business A home office for the first X months of the year, then when askes if you lived in the same home all 12 months say no and a drop down will appear and allow you to enter the second home. Then  enter the address of the new home and the number of months you used it for the rest of the year.  

You will then repeat for the second business.  

You will allocate the expenses to each business based on usage.  Meaning, if you use the office 20% for business A and 805 for business b, business A will get 20% of the expenses and business B will get 80%.  Both offices will be reported on the corresponding Schedule C. 

Can I claim the home office deduction for two or more businesses?