Q: My macbook white runs slow in the newest os.

You would need to further identify the exact model of the brand series and hardware configuration.

Perhaps you could post a report that would provide the basic information of your computer, the

installed memory, the hard drive capacity and how full the hard drive is of excess; and if there

is any incompatible software that made the trip along with your old files, that can't run in 10.11.

The report generated by http://etrecheck.com/#about may be helpful to see what you have there.

In general, performance issues can relate to incompatible software, scanning antivirus, adware

or malware-like products running in the background, browser extensions, and other errata.

• Apps can affect Mac performance, battery runtime, temperature, and fan activity - Apple Support

There is a Performance guide among three Tech Guides, that may be helpful as a brief or guide

to learn how to find out causes of a slow computer. Be sure you backup your content (and do not

move all the old junk into the computer when you upgrade to a new OS X or a new Mac.)

•Tech Guides - malware, adware & performance:

http://www.thesafemac.com/tech-guides/

If the computer is an old model and did not get a recommended hardware upgrade with more RAM

memory, or has a rather stuffed overfull hard drive storage, those are things to consider before one

gets a totally new operating system.

For your own information, you could enter your product serial number in this Identify by Serial Number

site to tell what it is and when it was made: https://www.powerbookmedic.com/identify-mac-serial.php

Assuming the MacBook in question was built between 2006 to 2010, has a 13-inch display and is

a Core2duo, its specs should be here, along with the newest 2015 that shares only the name:

• Apple MacBook Specs (All MacBook Technical Specs) from 2006 to 2015:

http://www.everymac.com/systems/apple/macbook/index-macbook.html

An Etrecheck report may help to become familiar with some aspects of your computer's working.

And others who view it may not have to ask for most of the basic details available to an owner.

Good luck & happy computing!