Vacant building bug
There is a bug where new construction remains “For Sale” and no one ever moves in. The buildings are not abandoned, they are never lived in. When occupied buildings get replaced with higher density buildings, the new buildings remain vacant, so the population goes down as the buildings grow. Eventually, there is not enough population to provide workers and commercial/industrial become abandonded and the whole city burns down (with all the fire stations closed). Once your city starts behaving this way, there is no correction and the issue spreads to the region. Even buldozing the city entirely and starting over does not fix the problem, so there is no option but to abandon the region. This was a problem in the Windows version back in 2013, but it is not fixed in this version, making the game unplayable.
cj0819 about SimCity™: Complete Edition