Thanks Steven!

I tried this:

Even though your system tells you that Safari is the default browser, try changing it to something different, e.g. Chrome or Firefox (and check the JuiceboxBuilder-Pro 'View in Browser' functionality after doing so), and then change it back to Safari.

But it did not work.
Selecting "View in browser" still opens the index.html-page in texteditor, and double-clicking on the index.html opens te gallery in the default browser. Still very strange....

Selecting "View in Browser"  does NOT open the gallery's 'index.html' file in the system's default browser. Instead it opens the index-file in the texteditor.

Yes I checked these two :

Please check that Safari 11 is your system's default browser by following the instructions on this Apple support page.
Also, check your system's file association for HTML files. It sounds like HTML files are currently associated with your text editor instead of Safari 11. Please check out this Apple support page for details, specifically the "Permanently change the app used to open a file" section.

Very strange. When I double-click on the index.html-file the gallery opens in the standard browser!

Can it be a language problem?

Yes! works now. I overlooked Safari's Local File Restrictions!! Thanks.

However there is still minor problem:

In the Publish-section I can check "View in Browser". When I do so, and safe the project, the text editor opens the project instead of my standard browser Safari.... Can this be changed?

Hi,

I just updated to to Juiceboxbuilder-Pro 1.5.1.   First I updated Adobe air, and uninstalled the previous version from Juicebox. And now I still can open the the files in Juiceboxbuilder-Pro 1.5.1, but i can not save them and/or view them in a browser. (MacBook Pro 10.11.6)

I tried deleting files like
~/Library/Application Support/Adobe/AIR/ELS/JuiceboxBuilder-Pro
~/Library/Preferences/JuiceboxBuilder-Pro

But that did not work.

JuiceboxBuilder-Pro wanted to use information stored in "Adobe.APS" in the keychain, but the keychain did not accept my password. very strange.. I have no idea what to try next.