I cannot update my MacBook
Whats the problem? I tried updating my MacBook multiple times. I had a repairing and the version went back to 10.15.7
MacBook Air 13″, macOS 10.15
Your post is in your High Sierra forum. An older system than Catalina (10.15.7), the operating system in your post.
If you are running Catalina, and it is not working well the first step is to determine what is wrong with your system first.
Etrecheck - the handy reporting tool for … - Apple Community
is able to diagnose most system issues, and gives you the opportunity to share information that people on this forum can use to help you diagnose it.