El Capitan upgrade fails!

[billc1023]

I've tried the upgrade (many hours!) five times and each ends in freezing my Macbook. I would like to roll back to Yosemite (and wait for El Capitan to mature) but Apple says the installer I downloaded from my Apple Apps purchases is not from Apple, and quits the install. Can anyone help me roll back to Yosemite? I haven't found any other source for downloading the install program. Thanks

 

[CoastalOR]

I've tried the upgrade (many hours!) five times and each ends in freezing my Macbook. I would like to roll back to Yosemite (and wait for El Capitan to mature) but Apple says the installer I downloaded from my Apple Apps purchases is not from Apple, and quits the install. Can anyone help me roll back to Yosemite? I haven't found any other source for downloading the install program. Thanks

Here's some instructions on how to revert to Yosemite (it assumes you previously downloaded Yosemite from the Apple App Store) and there is no problem with it, which seems is not to be the case.
http://www.macworld.co.uk/how-to/mac-software/delete-el-capitan-go-back-to-yosemite-3581872/

Probably the best solution is to restore from your Yosemite backup prior to the El Capitan upgrade.