App Store doesn't launch after El Capitan 10.11.1 update
This is the kind of 'random' error I would entrust to Onyx [freeware] to tackle.

Run the Utility, supply your admin password, then allow it to run the disk check.

After it has finished, go to Maintenance &amp; the 2nd tab, Permissions. Run the perms check.

If that is not sufficient to fix it, then try the default options in the last tab, Rebuilding.
Reboot.

Navigate to ~/Library/Saved Application State/com.apple.appstore.savedState &amp; delete the contents of that folder, not the folder itself.

 add a comment below if it still doesn't work