Can I use 365 days rental property if I tried to sell it for few months but couldn't sold. So I placed it on rent again and I never used it for personal use?

No. It must have still been available to rent.

Vacant while listed for sale. If you sell property you held for rental purposes, you can deduct the ordinary and necessary expenses for managing, conserving, or maintaining the property until it is sold. If the property is not held out and available for rent while listed for sale, the expenses are not deductible rental expenses.

PUB 527

Thanks for quick reply.

Just so I understand... I collected rent for 150 days in last year and it was for sell for rest 115 days from last year. So in this case my answer to the following question is 150, correct?

I tried changing days and it has no effect on my income from this rental 🙂 but just wanted to make sure I answer correctly in the software.

Yes, and personal days are zero.

What do I do for Expenses? Do I need to take proportionate expenses since I only rented for 150 days or can I claim full expenses? Is he same case for depreciation?

Thanks so much for quick reply