After a fresh installation of AIJ, be sure to update to the latest build

[karenacollins]

After installation of a full release of AIJ, be sure to use the AIJ update feature to update to the latest build. Follow these steps:

1) Start AIJ and go to the AIJ toolbar menu item: Help->Update AstroImageJ...
2) Select the latest version from the pull down menu
3) Click OK and 3 files will download and install
4) AIJ will then automatically close
5) When you start AIJ again, you will be running the new version

The 'daily build' in the pull down menu is the latest beta version. If you are having a particular problem, or just want to help out with beta testing, download that version rather than the highest numbered version. When you are running a daily build version, the AIJ version number will begin with "db" to indicate that it is a daily build.

Release notes are available by clicking the "Release Notes" button on the update panel.

[karenacollins]

If you encounter an error message when updating AIJ:

"Network Error!
Check your internet connection..."

and you have no internet connection problem, follow this post to resolve the one time problem.

http://astroimagej.1065399.n5.nabble.com/AstroimageJ-unable-to-update-td1080.html