Q: I update my MacBook to OS X El Capitan but i can't open my iphoto

That version of iPhoto is too old to run on El Capitan. You would need iPhotov9.6.1 for that, but to get that you would need to buy it and it's just not sold anymore.

With El Capitan you got the new Photos.app. It will open your iPhoto Library.

Yes Terence is spot on here I've just gone through the same experience of upgrading my iMac from Mountain Lion to Yosemite to discover that my iPhoto '09 app wouldn't work - but you can import the library into the new Photos app.

No you don't import the Library, you migrate it, simply by opening it with Photos.

You do not IMPORT libraries - you only Migrate them by opening them or dragging them to the Photos icon in the Dock - NEVER Import a library

LN

Any1, your only option now is to open your iPhoto Library in Photos for Mac.

As TD explained, only iPhoto 9.6.1 can run on OS X El Capitan and it is too late for you to upgrade to this version. Apple stopped selling iPhoto a year ago.  Only iPhoto '11 can be updated under certain conditions, because that is a free update and does not require to purchase the latest iPhoto release.

To open your iPhoto Library in Photos for Mac select the iPhoto Library in the Finder (by default your iPhoto Library will be in your Pictures folder),  then drag the iPhoto Library onto the Photos for Mac icon in your Dock.  The icon of your iPhoto Library will be different because of the olde version. It will also be a fan of three pictures, but colored like a sunset.

Photos will create a new, migrated library and open it in Photos.  This may take a while.  let it run.

See this help page on how to work with Photos:   Photos Help

This document explains how your iPhoto Library will be migrated to Photos for Mac:    How Photos handles content and metadata from iPhoto and Aperture - Apple Support

Post back, if you have more questions.

These user tips from Photos for Mac will help you in your transition from iPhoto to Photos:

Photos 1.5 vs iPhoto 9.6.1:  Features and Capabilities

Moments in Photos are the New Events

External Editors in Photos Are Here

Notes on Migrating an iPhoto Library from iPhoto to Photos for Mac

Photo Editing Extensions for Photos for Mac