Very slow boot and a slow performance after the latest OS upgrades

I have upgraded MacBook Air on few days back, but after upgrading it takes long time for booting and also several applications are unresponsive for a time and shows the busy. Previously it was working properly but now these kinds of problems I am facing. What should I check or reinstall? How can I solve this problem? If anyone knows, then please reply me. Any suggestion will appreciate. Thanks in advance.

There can be many reasons for this but I think the main reason for this is low space in your boot drive. I have seen that many of this kind of issues are raised due to the low space in the boot drive. I recommend you to perform the repair permission by going in to the disk utility option it will help you to clear all the caches and logs of your computer. There is a tool which is use to clear all logs and caches named “Cocktail” use it on your machine.

I have noticed that when opening certain programs in the system preferences take more time to get load and due to that booting can take more time for loading. Many programs like window firewall, network cause more time to start up the window. And also when you keep MBA on the sleep mode then also it takes more time to get start up. So If possible keep the system preference program off so that it can increase your boot time.

These issues can be due to the hard drive, I think you should check the log in console of your machine in that look for the all messages, if there is an I/O error found, and then it signals that your hard disk is going bad. If you found I/O error in console the contact with the Apple care to replace your hard disk drive and then check out the changes into your system. I am sure by doing so it helps you to solve your problems.

I suggest you to check the CPU usage of your machine. When your machine takes more than enough time for opening an application then I think it is using the very low memory of CPU. As far I know that CPU usage must be same as the ram usage of your machine, check that is your machine is using the sufficient CPU memory or not. You can found the CPU utilities in Applications/Utilities/Activity Monotor.app. And I also I suggest you to stop using the safari frequently. I hope this suggestion may help you.