Q: macbook is good to use but the problem with the speed it was bit slowly because update 10.11.5

Hi there, Julio!

I know how challenging a slow device can be whether it's an iOS device or a Mac. I'll be glad to help speed things up. Test your Mac after each step I've provided.

Use Time Machine to back up or restore your Mac -- Before starting any troubleshooting, it's always advisable to make a backup of your Mac to be sure your data is safe.

1. Reset the System Management Controller (SMC) on your Mac -- Resetting the SMC can help make sure your Mac starts up and works as it should.

2. How to Reset NVRAM on your Mac -- Resetting your Mac's NVRAM can also help speed things up.

3. Try safe mode if your Mac doesn‘t finish starting up​ -- If the issue is located in your startup disk, Safe Mode can help clear things up.

4. How to test an issue in another user account on your Mac -- If your Mac is still running slowly, testing in another user account can help determine if it's isolated to your user account or if it's throughout your Mac.

5. How to reinstall OS X​ -- If your Mac is still running slowly, reinstall the operating system again.

Thanks for using Apple Support Communities and have a great day!