I can't download Yosemite 10.2.3

After frequent attempts to download OS X 10.2.3, when asked to restart and I try to, I get the message "Available updates have changed". The "resent updates" in App Store shows every attempt to download it but "About this Mac" still shows my running OS X 10.2.2.

I have:

MacBook Air (13inch early 2014)

Proc: 1,4 GHz intel core i5

Mem: 8GB 1600 MHz DDR3

Graphics: Intel HD Graphics 500 1536 MB

I would really appreciate some help.