nfh85

Level 1 (4 points)

Mac OS X

Q: Cannot downgrade from El Capitan to Mountain Lion!

After installing El Capitan, my Mac Book Pro (perfectly working before) slowed down so much that it is almost not useable anymore. I thought I could 'downgrade' again to Mountain Lion to get the old speed back. However, it seems not possible to change the OS. It informs me the 'install' software is too old to run on El Capitan.

Any ideas what to do?!

MacBook Pro, OS X El Capitan (10.11)

Posted on Jul 22, 2016 1:03 PM

I have this question too

Q: Cannot downgrade from El Capitan to Mountain Lion!

All replies

Helpful answers

by Eric Root,

Eric Root Jul 22, 2016 5:31 PM in response to nfh85
Level 9 (69,881 points)

iTunes

Jul 22, 2016 5:31 PM in response to nfh85

Revert

OS X El Capitan: Revert to a previous OS X version

Troubleshooting El Capitan slowness.

Activity Monitor - Mavericks also Yosemite

Activity Monitor in Mavericks has significant changes

Performance Guide

Why is my computer slow

Why your Mac runs slower than it should

Slow Mac After Mavericks

Things you can do to resolve slowdowns see post by Kappy

6 Easy Tips to Speed Up OS X Yosemite on Your Mac

OS X El Capitan: If your Mac runs slowly

Try running this program and then copy and paste the output in a reply. The program was created by Etresoft, a frequent contributor. Please use copy and paste as screen shots can be hard to read.

Etrecheck – System Information
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