I recently upgraded to mavericks on iMac . now when i open aperture I get the message"aperture cannot access this library. to use this library, make sure its file permissions are set correctly" I have repaid permissions via the aperture first aid. I notic

I notice my short user name has changed from the one before the mavericks upgrade.

Then you created a new user account when upgrading. How did you upgrade? Did erase the system and set up your mac completely new? If your short user name has changed, you are no longer the owner of your Aperture library, if it ha been created with your old user name.

I repaired the permissions in aperture first aid.

And after repairing the permissions you can still not access it?

Where is the library located? On an external drive or in your Home folder?

Since it appears you have changed account (names) you may need to reset permissions for the Aperture Library and/or the drive on which it resides in the Finder.

Right-click on the library name or drive name. Choose 'Get Info'. You'll then see the attached window. Look to the bottom of it. If your computer short name doesn't apper there click on the 'Lock' and when that opens click on the '+' to add it. Give it 'Read & Write' permissions. You may need to do the same for the drive unless it is your sytem drive.