Sounds to me like you may have mis-understood what the program is asking for, since you converted it to personal use mid-year. The program does lack clarify in that respect. So here's the clarity.
THe business use percentage of the property on 100%. (one hundred percent). It's asking for the percentage of time you used the property for business *before* you converted it to personal use. So it's 100% business use. This is assuming that you did not live in the property for one single day as your primary residence, 2nd home or vacation home *before* you converted it to personal use.
Number of days rented will be counted from Jan 1st, to the date of one day before you converted it to personal use, or if your took it "out of service" before that date, then it will be the days counting from Jan 1st, to the day *before* you took the property out of service. Since you converted it to personal use, the property is considered out of service on the date the last renter moved out. Any expenses incurred after that date are not deductible rental expenses. This is true even if your conversion date, is a date after the out-of-service date.
Pay attention to the screens that ask you for your mortgage interest. Depending on what you selected at the start of the rental section, you will be told to enter the total amount of interest paid and if so, the program will pro-rate it for you. Otherwise, if you elected to do the splits yourself manually, the screen will inform you that you have to manually figure it.
In the "rental expenses" section, you only claim those expenses incurred before you took the property out of service. One thing to pay attention to is the property insurance and real estate taxes. You "might" have to pro-rate those manually, or the program will do it for you depending on what you selected at the start of the rental section. I do know that in the desktop version of the program, the program will not pro-rate the property taxes and insurance for you, no matter what you selected at the start of the rental section. I would expect that to be true for the online version of TurboTax also.