after 4 months I turned on my MacBook Air  and first off all I tried install JDK 8 and Eclipse for developing python. after all things done, I notified by app store update notification so I clicked to update all of applications. but this things happened.
- after downloading all files, iTunes 12.8.2, Safari 12.0.3 and Security Update 2019-001 10.12.6 it shows this message:
- ok, now everything is good and waiting for progress bar to complete:
- and after downloading things wait for restart:
- it shows OS update progress:
- and error happened :
- MacBook restarted and go to MacOS again
- and now this message showing up:
- and now if i click on install, it goes to step one again. and everything repeated as I said in this list.
- MacOS Sierra 10.12.6
- MacBook Air (13 inch - early 2015)
- 8Gb DDR3
- and about 20Gb free space